Uva-ursi extract and ibuprofen as alternative treatments for uncomplicated urinary tract infection in women (ATAFUTI): a factorial randomized trial.

OBJECTIVES: The aim was to investigate if offering symptomatic therapy (Uva-ursi or ibuprofen) alongside a delayed prescription would relieve symptoms and reduce the consumption of antibiotics for adult women presenting with acute uncomplicated urinary tract infection (UTI). METHODS: A 2 × 2 factorial placebo controlled randomized trial in primary care. The participants were 382 women aged 18-70 years with symptoms of dysuria, urgency, or frequency of urination and suspected by a clinician to have a lower UTI. The interventions were Uva-ursi extract and/or ibuprofen advice. All women were provided with a delayed or 'back-up' prescription for antibiotics. Missing data were imputed using multiple imputation methods (ISRCTN registry: ISRCTN43397016). RESULTS: An ITT analysis of mean score for frequency symptoms assessed on Days 2-4 found no evidence of a difference between Uva-ursi vs. placebo -0.06 (95% CI -0.33 to 0.21; p 0.661), nor ibuprofen vs. no ibuprofen advice -0.01 (95% CI -0.27 to 0.26; p 0.951). There was no evidence of a reduction in antibiotic consumption with Uva-ursi (39.9% vs. placebo 47.4%; logistic regression odds ratio (OR) 0.59 (95% CI 0.22-1.58; p 0.293) but there was a significant reduction for ibuprofen advice (34.9% vs. no advice 51.0%; OR 0.27 (95% CI 0.10 to 0.72; p 0.009). There were no safety concerns and no episodes of upper tract infection were recorded. CONCLUSIONS: We found no evidence of an effect of either intervention on the severity of frequency symptoms. There is evidence that advice to take ibuprofen will reduce antibiotic consumption without increasing complications. For every seven women given this advice, one less will use antibiotics.

The persistence of the effects of acupuncture after a course of treatment: a meta-analysis of patients with chronic pain.

There is uncertainty regarding how long the effects of acupuncture treatment persist after a course of treatment. We aimed to determine the trajectory of pain scores over time after acupuncture, using a large individual patient data set from high-quality randomized trials of acupuncture for chronic pain. The available individual patient data set included 29 trials and 17,922 patients. The chronic pain conditions included musculoskeletal pain (low back, neck, and shoulder), osteoarthritis of the knee, and headache/migraine. We used meta-analytic techniques to determine the trajectory of posttreatment pain scores. Data on longer term follow-up were available for 20 trials, including 6376 patients. In trials comparing acupuncture to no acupuncture control (wait-list, usual care, etc), effect sizes diminished by a nonsignificant 0.011 SD per 3 months (95% confidence interval: -0.014 to 0.037, P = 0.4) after treatment ended. The central estimate suggests that approximately 90% of the benefit of acupuncture relative to controls would be sustained at 12 months. For trials comparing acupuncture to sham, we observed a reduction in effect size of 0.025 SD per 3 months (95% confidence interval: 0.000-0.050, P = 0.050), suggesting approximately a 50% diminution at 12 months. The effects of a course of acupuncture treatment for patients with chronic pain do not seem to decrease importantly over 12 months. Patients can generally be reassured that treatment effects persist. Studies of the cost-effectiveness of acupuncture should take our findings into account when considering the time horizon of acupuncture effects. Further research should measure longer term outcomes of acupuncture.

Complementary and alternative healthcare use by participants in the PACE trial of treatments for chronic fatigue syndrome.

BACKGROUND: Chronic Fatigue Syndrome (CFS) is characterised by persistent fatigue, disability and a range of other symptoms. The PACE trial was randomised to compare four non-pharmacological treatments for patients with CFS in secondary care clinics. The aims of this sub study were to describe the use of complementary and alternative medicine (CAM) in the trial sample and to test whether CAM use correlated with an improved outcome. METHOD: CAM use was recorded at baseline and 52weeks. Logistic and multiple regression models explored relationships between CAM use and both patient characteristics and trial outcomes. RESULTS: At baseline, 450/640 (70%) of participants used any sort of CAM; 199/640 (31%) participants were seeing a CAM practitioner and 410/640 (64%) were taking a CAM medication. At 52weeks, those using any CAM fell to 379/589 (64%). Independent predictors of CAM use at baseline were female gender, local ME group membership, prior duration of CFS and treatment preference. At 52weeks, the associated variables were being female, local ME group membership, and not being randomised to the preferred trial arm. There were no significant associations between any CAM use and fatigue at either baseline or 52weeks. CAM use at baseline was associated with a mean (CI) difference of 4.10 (1.28, 6.91; p=0.024) increased SF36 physical function score at 52weeks, which did not reach the threshold for a clinically important difference. CONCLUSION: CAM use is common in patients with CFS. It was not associated with any clinically important trial outcomes.

Chinese herbal medicine for idiopathic sudden sensorineural hearing loss: a systematic review of randomised clinical trials.

BACKGROUND: Idiopathic sudden sensorineural hearing loss has great impact on quality of life. Many clinical trials using Chinese herbal medicine for idiopathic sudden sensorineural hearing loss have been conducted and reported beneficial results. However, there is no critical appraised evidence on efficacy and safety of Chinese herbal medicine for idiopathic sudden sensorineural hearing loss to inform clinical use. OBJECTIVE OF REVIEW: To assess the beneficial effect and safety of Chinese herbal medicine for idiopathic sudden sensorineural hearing loss. TYPE OF REVIEW: Systematic review of randomised clinical trials. SEARCH STRATEGY: Seven electronic databases and two trial registries were searched for all eligible trials from inception to January 2013. EVALUATION METHOD: Two authors independently selected trials and extracted data. The Cochrane risk of bias tool was utilised to assess the methodological quality of the included trials. revman 5.2 software was applied for data analysis with effect estimate presented as risk ratio and mean difference with its 95% confidence interval. RESULTS: Forty-one randomised clinical trials involving 3560 participants were identified. Five kinds of Chinese herbal medicine were trialed. All trials compared conventional therapies of steroids, vasodilators, anticoagulants, nutritional supplements or hyperbaric oxygen with or without herbal medicine. No trial was identified that compared herbal medicine alone with placebo. No trial was identified that blinded the participants or the observers to their herbal medication. Only one trial adequately reported its method of randomisation. No trial reported the sample size calculated to show an effect. All trials had material other defects giving a high likelihood of bias. Because of the overall poor quality of all 41 trials, it was concluded that there was no level-one evidence to support the use of Chinese herbal medicine, alone or in addition to conventional therapies, to improve the hearing in adults with idiopathic sudden sensorineural hearing loss. Two trials reported adverse effects, and no severe adverse effects were found in the Chinese herbal medicine groups. CONCLUSIONS: The existing evidence for the beneficial effect and safety of Chinese herbal medicine for idiopathic sudden sensorineural hearing loss comes from methodologically poor studies and therefore cannot be reliably used to support their clinical use. We identify a justification to further investigate the effect and safety of Chinese herbal medicine for people with idiopathic sudden sensorineural hearing loss in rigorously designed randomised trials.

Professional kinesiology practice for chronic low back pain: single-blind, randomised controlled pilot study.

BACKGROUND: Chronic low back pain is a highly prevalent condition with no definitive treatment. Professional Kinesiology Practice (PKP) is a little known complementary medicine technique using non-standard muscle testing; no previous effectiveness studies have been performed. METHODS: This is an exploratory, pragmatic single-blind, 3-arm randomised sham-controlled pilot study with waiting list control (WLC) in private practice UK (2007-2009). 70 participants scoring ≥4 on the Roland and Morris Disability Questionnaire (RMDQ) were randomised to real or sham PKP receiving 1 treatment weekly for 5 weeks or a WLC. WLC's were re-randomised to real or sham after 6 weeks. The main outcome was a change in RMDQ from baseline to end of 5 weeks of real or sham PKP. RESULTS: With an effect size of 0.7 real treatment was significantly different to sham (mean difference RMDQ score = -2.9, p = 0.04, 95% CI -5.8 to -0.1). Compared to WLC, real and sham groups had significant RMDQ improvements (real -9.0, p < 0.01, 95% CI -12.1 to -5.8; effect size 2.1; sham -6.1, p < 0.01, 95% CI -9.1 to -3.1; effect size 1.4). Practitioner empathy (CARE) and patient enablement (PEI) did not predict outcome; holistic health beliefs (CAMBI) did, though. The sham treatment appeared credible; patients did not guess treatment allocation. 3 patients reported minor adverse reactions. CONCLUSIONS: Real treatment was significantly different from sham demonstrating a moderate specific effect of PKP; both were better than WLC indicating a substantial non-specific and contextual treatment effect. A larger definitive study would be appropriate with nested qualitative work to help understand the mechanisms involved in PKP.

Complementary medicine use by men with prostate cancer: a systematic review of prevalence studies.

Men with prostate cancer are reported as commonly using complementary and alternative medicine (CAM) but surveys have not recently been subjected to a rigorous systematic review incorporating quality assessment. Six electronic databases were searched using pre-defined terms. Detailed information was extracted systematically from each relevant article. Study reporting quality was assessed using a quality assessment tool, which demonstrated acceptable inter-rater reliability and produces a percentage score. In all, 42 studies are reviewed. All were published in English between 1999 and 2009; 60% were conducted in the United States. The reporting quality was mixed (median score = 66%, range 23-94%). Significant heterogeneity precluded formal meta-analysis. In all, 39 studies covering 11,736 men reported overall prevalence of CAM use; this ranged from 8 to 90% (median=30%). In all, 10 studies reported prevalence of CAM use specifically for cancer care; this ranged from 8 to 50% (median = 30%). Some evidence suggested CAM use is more common in men with higher education/incomes and more severe disease. The prevalence of CAM use among men with prostate cancer varies greatly across studies. Future studies should use standardised and validated data collection techniques to reduce bias and enhance comparability.

Ear-acupressure for allergic rhinitis: a systematic review.

BACKGROUND: Allergic rhinitis affects 10-40% of the population globally with a substantial health and economic impact on the community. OBJECTIVE OF REVIEW: To assess the effectiveness and safety of ear-acupuncture or ear-acupressure for the treatment of allergic rhinitis by reviewing randomised controlled trials and quasi-randomised controlled trials. TYPE OF REVIEW: This review followed the methods specified in the Cochrane Handbook for Systematic Reviews of Interventions. SEARCH STRATEGY: A total of 21 electronic English and Chinese databases were searched from their respective inceptions to April 2008. Key words used in the search included the combination of ear, auricular, acupuncture, acupressure, acupoint, allergic, allergy, rhinitis, hayfever, randomised clinical trial and their synonyms. EVALUATION METHOD: The methodological quality was assessed using Jadad's scale. The effect size analysis was performed to explore the difference between interventional groups. RESULTS: Ninety-two research papers were identified and seven of them referring to five studies met the inclusion criteria. All included studies involved ear-acupressure treatment. These studies mentioned randomisation, but no details were given. None of the five studies used blinding or intention-to-treat analysis. Ear-acupressure was more effective than herbal medicine, as effective as body acupuncture or antihistamine for short-term effect, but it was more effective than anti-histamine for long-term effect. CONCLUSIONS: The benefit of ear-acupressure for symptomatic relief of allergic rhinitis is unknown due to the poor quality of included studies.

Who Uses CAM? A Narrative Review of Demographic Characteristics and Health Factors Associated with CAM Use.

Complementary and Alternative Medicines (CAM) are used by an extensive number of patients in the UK and elsewhere. In order to understand this pattern of behavior, it is helpful to examine the characteristics of people who use CAM. This narrative review collates and evaluates the evidence concerning the demographic characteristics and health status factors associated with CAM use in community-based non-clinical populations. A systematic literature search of computerized databases was conducted, and published research papers which present evidence concerning associations between CAM use and demographic and health characteristics are discussed and evaluated. The evidence suggests that people who use CAM tend to be female, of middle age and have more education. In terms of their health, CAM users tend to have more than one medical condition, but might not be more likely than non-users to have specific conditions such as cancer or to rate their own general health as poor. The multivariate studies that have been conducted suggest that both demographic and health characteristics contribute independently to CAM use. In conclusion, demographic characteristics and factors related to an individual's health status are associated with CAM use. Future research is needed to address methodological limitations in existing studies.

Patterns of complementary and alternative medicine use among patients undergoing cancer treatment.

This study aimed to assess the prevalence of complementary and alternative medicine (CAM) use in a representative cancer population prior to and within 6 months of diagnosis. A total of 304 newly diagnosed cancer patients from two UK cancer centres completed a postal survey. Of them, 100 patients (32.9%) used CAM before their cancer diagnosis, 59 of these CAM users continued post diagnosis. Twenty-nine individuals who had not used CAM before began to use it after their cancer diagnosis, creating a total of 88 (28.9%) CAM users in this sample. Reasons for not using CAM included lack of interest, lack of information or endorsement from professionals and satisfaction with conventional care. For those using CAM before diagnosis but not afterwards, the most common reason was a lack of expert guidance on what was safe to use. The use of CAM medicines bought from health food and other retail outlets was high. Complementary and alternative medicine use in cancer patients is common and demonstrates a complex pattern, but CAM use is not significantly greater than in the general population. Some patients purchase CAM medicines without seeking medical advice, thus risking drug interactions. Research to generate information on safety and efficacy of CAM is required.

Evaluating the efficacy of acupuncture in defined aspects of stroke recovery: a randomised, placebo controlled single blind study.

OBJECTIVE: To investigate the efficacy of acupuncture on stroke recovery compared to an inert placebo. DESIGN: Placebo-controlled, randomised, clinical trial. SETTING: Post-stroke rehabilitation wards in five NHS hospitals in the UK. SUBJECTS: Patients between 4 and 10 days after their first stroke. INTERVENTIONS AND OUTCOME MEASURES: The patients received 12 acupuncture or placebo treatments over four weeks. Acupuncture with electrical stimulation was compared with mock TENS, and assessments continued for 12 months after entry. Primary outcome was the Barthel Index (BI). Secondary outcomes were muscle power, Motricity Index (MI), mood, Nottingham Health Profile (NHP) and treatment credibility. RESULTS: 92 patients completed data sets. Data were analysed using both t tests and a structural equation based on longitudinal analysis of both BI and MI, using generalised estimating equations with an exchangeable correlation structure. While both acupuncture and placebo (mock TENS) appeared to have had an equal effect on stroke recovery, there is no significant difference between the two interventions at 12 (p = 0.737, 95 % CI -2.00 to 2.81) and 52 weeks (p = 0.371, 95 % CI -3.48 to 1.32). An apparently accelerated improvement in the MI scores in the acupuncture group at 3 weeks (p = 0.009, 95 % CI 1.55 to 10.77) is interesting. CONCLUSIONS: Acupuncture did not demonstrate specific efficacy over placebo and both groups did as well as normally expected with this condition.

Systematic review of the nutritional supplements dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of osteoarthritis.

OBJECTIVE: Conventional treatment of osteoarthritis (OA) with non-steroidal anti-inflammatory drugs is associated with serious gastrointestinal side effects and in view of the recent withdrawal of some cyclo-oxygenase-2 inhibitors, identifying safer alternative treatment options is needed. The objective of this systematic review is to evaluate the existing evidence from randomised controlled trials of two chemically related nutritional supplements, dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of OA to determine their efficacy and safety profile. METHODS: The electronic databases [Cochrane Library, Medline, Embase, Amed, Cinahl and NeLH (1950 to November 2007)] were searched. The search strategy combined terms: osteoarthritis, degenerative joint disorder, dimethyl sulfoxide, DMSO, methylsulfonylmethane, MSM, clinical trial; double-blind, single blind, RCT, placebo, randomized, comparative study, evaluation study, control. Inclusion and exclusion criteria were applied. Data were extracted and quality was assessed using the JADAD scale. RESULTS: Six studies were included [evaluating a total of 681 patients with OA of the knee for DMSO (N=297 on active treatment); 168 patients for MSM (N=52 on active treatment)]. Two of the four DMSO trials, and both MSM trials reported significant improvement in pain outcomes in the treatment group compared to comparator treatments, however, methodological issues and concerns over optimal dosage and treatment period, were highlighted. CONCLUSION: No definitive conclusion can currently be drawn for either supplement. The findings from all the DMSO studies need to be viewed with caution because of poor methodology including; possible unblinding, and questionable treatment duration and dose. The data from the more rigorous MSM trials provide positive but not definitive evidence that MSM is superior to placebo in the treatment of mild to moderate OA of the knee. Further studies are now required to identify both the optimum dosage and longer-term safety of MSM and DMSO, and definitive efficacy trials.

A systematic review of vanadium oral supplements for glycaemic control in type 2 diabetes mellitus.

OBJECTIVE: To assess the effectiveness of oral vanadium supplementation for glycaemic control in type 2 diabetes by conducting a systematic review of the literature. DESIGN AND METHODS: Eligible studies were identified by searching 14 databases using standardized terms. Experts, study authors and manufacturers were also contacted. Hand-searching was not undertaken. Selection criteria for inclusion in the review were controlled human trials of vanadium vs. placebo in adults with type 2 diabetes of minimum 2 months duration, and a minimum of 10 subjects per arm. Data extraction, assessment of study quality and outcome analysis were undertaken by two independent reviewers. RESULTS: One hundred and fifty one studies were found but none met the inclusion criteria. We proceeded to summarize the state of existing evidence and plan for a future clinical trial by applying revised, less restrictive criteria to our search, for clinical trials of 30-150 mg daily oral vanadium supplementation in diabetic humans. Only five were identified. These demonstrated significant treatment-effects, but due to poor study quality, must be interpreted with caution. Treatment with vanadium often results in gastrointestinal side-effects. CONCLUSION: There is no rigorous evidence that oral vanadium supplementation improves glycaemic control in type 2 diabetes. The routine use of vanadium for this purpose cannot be recommended. A large-scale randomized controlled trial is needed to address this clinical question.

Systematic review of the nutritional supplement Perna Canaliculus (green-lipped mussel) in the treatment of osteoarthritis.

Complementary treatments for osteoarthritis (OA) are sought by patients for symptomatic relief and to avoid the iatrogenic effects of non-steroidal anti-inflammatories. This systematic review evaluates the efficacy of the nutritional supplement Perna Canaliculus (green-lipped mussel, GLM) in the treatment of OA and substantially adds to previous work by focussing solely on GLM use in OA as well providing a re-analysis of the original trial data. Randomized or quasi-randomized controlled trials (comparative, placebo-controlled or crossover) were considered for inclusion from Cochrane Library, Medline, Embase, Amed, Cinahl, Scopus and NeLH databases where adults with OA of any joint were randomized to receive either GLM vs. placebo, no additional intervention (usual care), or an active intervention. The methodological quality of the trials was assessed using the JADAD scale. Four RCTs were included, three placebo controlled, the fourth a comparative trial of GLM lipid extract vs. stabilized powder extract. No RCTs comparing GLM to conventional treatment were identified. All four studies assessed GLM as an adjunctive treatment to conventional medication for a clinically relevant time in mild to moderate OA. All trials reported clinical benefits in the GLM treatment group but the findings from two studies cannot be included in this review because of possible un-blinding and inappropriate statistical analysis. The data from the two more rigorous trials, in conjunction with our re-analysis of original data suggests that GLM may be superior to placebo for the treatment of mild to moderate OA. As a credible biological mechanism exists for this treatment, further rigorous investigations are required to assess efficacy and optimal dosage.

Bromelain as an adjunctive treatment for moderate-to-severe osteoarthritis of the knee: a randomized placebo-controlled pilot study.

BACKGROUND: Osteoarthritis (OA) of the knee is the most prevalent joint disorder. Previous studies suggest that bromelain, a pineapple extract, may be a safer alternative/adjunctive treatment for knee OA than current conventional treatment. AIM: To assess the efficacy of bromelain in treating OA of the knee. DESIGN: Randomized, double-blind placebo-controlled trial. METHODS: Subjects (n = 47) with a confirmed diagnosis of moderate to severe knee OA were randomized to 12 weeks of bromelain 800 mg/day or placebo, with a 4-week follow-up. Knee (pain, stiffness and function) and quality-of-life symptoms were reported monthly in the WOMAC and SF36 questionnaires, respectively. Adverse events were also recorded. The primary outcome measure was the change in total WOMAC score from baseline to the end of treatment at week 12. Longitudinal models were used to evaluate outcome. RESULTS: Thirty-one patients completed the trial (14 bromelain, 17 placebo). No statistically significant differences were observed between groups for the primary outcome (coefficient 11.16, p = 0.27, 95%CI -8.86 to 31.18), nor the WOMAC subscales or SF36. Both treatment groups showed clinically relevant improvement in the WOMAC disability subscale only. Adverse events were generally mild in nature. DISCUSSION: This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA, but its limitations support the need for a follow-up study.

Could neuroimaging help us to interpret the clinical effects of acupuncture?

One of the problems in assessing acupuncture efficacy has been the lack of a standardised placebo/control. Despite the lack of 'proof', acupuncture is widely used; hence it would seem that a large proportion of the public are not too concerned with the question of efficacy. Patients and researchers approach the issue of whether acupuncture "works" in an entirely different way. It may be that the management of chronic pain as a whole is largely context driven and non-specific. Therefore, research should focus on areas such as pragmatic/comparative trials and the non-specific effects of treatment. Improving our understanding of the neural mechanisms and substrates of acupuncture, placebo and non-specific effects might enable us to better define a "true placebo" and improve trial design. Imaging studies, however, need to be much more pragmatic. Because of the large overlap in areas of brain activated through acupuncture, pain, placebo and non-specific factors, separating these out in an attempt to pinpoint the mechanisms behind acupuncture will be difficult. Ultimately we need a balance between efficacy, comparative and mechanistic trials using imaging work to inform the whole picture. A broader view of research is therefore necessary to yield meaningful answers and we need to look at the whole package that acupuncture delivers.

A placebo-controlled, double-blind, randomized controlled trial of a natural killer cell stimulant (BioBran MGN-3) in chronic fatigue syndrome.

BACKGROUND: Previous research has suggested that natural killer (NK) cell activity may be reduced in patients with chronic fatigue syndrome (CFS). AIM: To evaluate the effectiveness of a putative NK cell stimulant, BioBran MGN-3, in reducing fatigue in CFS patients. DESIGN: Randomized, double-blind, placebo-controlled trial. METHODS: We recruited 71 patients with CFS (according to the Centers for Disease Control 1994 criteria) attending an out-patient specialist CFS service. Participants were given oral BioBran MGN-3 for 8 weeks (2 g three times per day) or placebo equivalent. The primary outcome measure was the Chalder physical fatigue score. Self-reported fatigue measures, self-assessment of improvement, change in key symptoms, quality of life, anxiety and depression measures were also included. RESULTS: Data were complete in 64/71 patients. Both groups showed marked improvement over the study duration, but without significant differences. Mean improvement in the Chalder fatigue score (physical scale) was 0.3 (95%CI -2.6 to 3.2) lower in the BioBran group. DISCUSSION: The findings do not support a specific therapeutic effect for BioBran in CFS. The improvement showed by both groups over time highlights the importance of placebo controls when evaluating interventions in CFS.

Developing a measure of treatment beliefs: the complementary and alternative medicine beliefs inventory.

OBJECTIVES: The study aimed to develop a comprehensive generic measure of treatment beliefs, the Complementary and Alternative Medicine Beliefs Inventory (CAMBI), and to identify distinct dimensions of CAM-related beliefs. METHODS: The CAMBI and other measures were presented and advertised online. RESULTS: 328 completed questionnaires were received. Factor analysis indicated three dimensions of beliefs could be identified. Subscales of the CAMBI were developed measuring beliefs in natural treatment, participation in treatment and holistic health. The subscales all had satisfactory reliability and were significantly correlated with CAM use (Spearman's rho=.18, .47 and .22 for natural treatments, holistic health and participation in treatment, respectively). CONCLUSIONS: The CAMBI measures three distinct dimensions of treatment beliefs, all of which are related to CAM use.

Presentiment or entanglement? An alternative explanation for apparent entanglement in provings.

A number of authors have recently discussed the possible role entanglement in homeopathy. Walach et al have published a homeopathic proving which they interpreted as demonstrating entanglement between placebo and verum groups in a proving. The lack of a 'run-in' period was a weakness of this trial. We present further results of our proving of Belladonna which show that subjects who reported symptoms during the placebo run-in period ('presentiment provers') were more likely to report symptoms during the treatment period. This data suggests and the observations of Walach et al may be explicable by conventional mechanisms including differential reporting and constitutional type.

The Buteyko breathing technique for asthma: a review.

Breathing exercises and breathing retraining are often used in the management of asthma. One specific form of breathing therapy, known as the Buteyko breathing technique (BBT) has received considerable attention, but there is a paucity of rigorous research evidence to support its recommendation for asthma patients. There are only four published clinical trials and two conference abstracts evaluating BBT. Although all have reported improvements in one or more outcome measures, results have not been consistent. This article provides the background to the BBT, reviews the available evidence for its use and examines the physiological hypothesis claimed to underpin it. In common with other therapies, BBT is not a standardised treatment modality. The BBT 'package' is complex, as it also includes advice and education about medication use, nutrition and exercise, and general relaxation. This makes it difficult, and possibly inappropriate, to attempt to tease out a single mechanism. Buteyko's theory relating to carbon dioxide levels and airway calibre is an attractive one, and has some basis in evidence from experimental studies. However, it is not known whether altering breathing patterns can raise carbon dioxide levels significantly, and there is currently insufficient evidence to confirm that this is the mechanism behind any effect that BBT may exert. Further research is necessary to establish unequivocally whether BBT is effective, and if so, how it may work.