Fibronectin Gene Up-regulation by Arnica montana in Human Macrophages: Validation by Real-Time Polymerase Chain Reaction Assay.

BACKGROUND AND AIM: Arnica montana L. (Arnica m.) is a popular traditional medicine, used for its therapeutic properties in healing traumas, but little is known about its biological action on tissue formation and repair. This new work tested the effects of Arnica m. homeopathic dilutions on human macrophages, key cells in tissue defence and repair. MATERIALS AND METHODS: Macrophages derived from the THP-1 cell line were differentiated with interleukin-4 to induce a 'wound-healing'-like phenotype, and treated with various dilutions of Arnica m. centesimal (100 times) dilutions (2c, 3c, 5c, 9c, and 15c) or control solvent for 24 hours. RNA samples from cultured cells were analysed by real-time quantitative polymerase chain reaction in five separate experiments. RESULTS: Arnica montana at the 2c dilution (final concentration of sesquiterpene lactones in cell culture = 10-8 mol/L) significantly stimulated the expression of three genes which code for regulatory proteins of the extracellular matrix, namely FN1 (fibronectin 1, % increase of 21.8 ± standard error of the mean 4.6), low-density lipoprotein-receptor-related protein 1 (% increase of 33.4 ± 6.1) and heparan sulphate proteoglycan 2 (% increase of 21.6 ± 9.1). Among these genes, the most quantitatively expressed was FN1. In addition, FN1, unlike other candidate genes, was upregulated in cells treated with higher dilutions/dynamisations (3c, 5c, and 15c) of Arnica m. CONCLUSION: The results support evidence that the extracellular matrix is a potential therapeutic target of Arnica m., with positive effects on cell adhesion and migration during tissue development and healing.

Comments on the Retraction by PLoS ONE of a Laboratory Study on Arnica montana.

In June 2019, the journal PLoS ONE retracted an original research article, published in 2016, which described the effects of homeopathic Arnica montana on interleukin-4 treated human macrophages. The results showed an increase in extracellular matrix gene expression, including the gene encoding fibronectin, which is one of the main proteins involved in connective tissue healing. Here, the authors of the article discuss the critical points raised by the journal in the retraction note, with a focus on the specific methodological aspects of research on high dilutions of natural compounds. The editorial arguments made to justify the retraction did not prove any methodological errors, nor scientific misconduct. As a general rule, when a study published by a group of researchers raises scientific doubts because the results appear at variation with the commonly accepted knowledge in a field, the study is repeated by other scholars and any contrasting results are published and/or discussed. Therefore, retraction of the Arnica m. study by PLoS ONE is a violation of the conventions of scientific publication and knowledge-sharing methods derived from honest experimental method.

A Pilot Study of Prospective Data Collection by Italian Homeopathic Doctors.

OBJECTIVE: The main purpose of this article is to report the systematic data collection pertaining to the consultations of a group of qualified homeopathic physicians. Studies have been performed concerning: (1) the most frequently treated pathologies; (2) the symptoms reported by patients, with a particular focus on "fear" symptoms; and (3) the evaluation of the outcomes of the treatment, including likelihood ratio (LR) for fear symptoms of mostly prescribed remedies. DESIGN: Prospective observational study. SETTING: Individualized homeopathic treatment at private homeopathic surgeries in Italy. PARTICIPANTS: Adult patients asking for homeopathic therapy for a series of common ailments. OUTCOME MEASURES: Types of diseases and remedies used and clinical parameters (frequency of acute attacks, and their intensity and duration); the overall outcome of the cure was registered using the Outcome Related to Impact on Daily Living (ORIDL) scale. RESULTS: Only 94 patients could be enrolled by eight homeopathic doctors in a 2-year period between 2015 and 2017. Ninety (72 females, 18 males) patients completed the observation period. The most represented pathologies belonged to the group "Anxiety and anxiety disorders" followed by gastrointestinal ailments. The most prescribed remedy was Phosphorus (9 cases), followed by Natrum muriaticum (4 cases) and Ignatia (4 cases). The intensity of the symptoms and the frequency of the attacks decreased during the course of the study. Most patients reported a positive outcome (ORIDL scale). In the "Phosphorus" group, LR values were calculated for fear symptoms: LR+ for fear of dark = 2.25 (95% confidence interval [CI] = 0.56 to 9.02), LR- for fear of crowds = 1.27 (95% CI = 1.13 to 1.42), and LR- for fear of ghosts = 1.12 (95% CI = 1.04 to 1.22). CONCLUSION: The recruited group was smaller than expected, but data from most participants could be collected. Positive clinical outcomes were recorded and LR of a few specific fears contributed to distinguish Phosphorus patients from the remaining population.

In vitro effects of Zinc in soluble and homeopathic formulations on macrophages and astrocytes.

Zinc is an important metal in body homeostasis. Zinc in soluble form (Zn2+) and homeopathic Zincum metallicum were tested in macrophages and astrocytes in order to investigate its potential toxic or therapeutic effects. We evaluated cell viability (WST assay), cytokine production such as tumour necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) by enzyme-linked immunosorbent assay (ELISA) and nitric oxide release by Griess reaction. The effect of zinc-depletion and high zinc pre-treatments on the cell adaptation capability was also investigated. In THP-1 macrophage cell line and in human primary macrophages, Zn2+ at sub-toxic doses (30 µM) caused stimulation of TNF-α and IL-10 with different dynamics reaching the maximum peak at the zinc concentration 100 µM, before the cell death. Highest doses (300 µM) impaired dramatically cell vitality. Similar effects on cell viability were obtained also in C6 astrocytes, where Zn2+ slightly increased the nitric oxide release only in cells activated by one of the pro-inflammatory stimuli used in our cellular model (interferon gamma plus TNF-α). Zinc depletion markedly reduced IL-10 production and cell viability. Zincum metallicum did not cause toxicity in any cell type and showed some small stimulation in WST assay that was statistically significant in a few experimental conditions.

Number of succussion strokes affects effectiveness of ultra-high-diluted arsenic on in vitro wheat germination and polycrystalline structures obtained by droplet evaporation method.

OBJECTIVES: The aim of this study is to investigate whether the number of succussion strokes applied after each dilution step when preparing the homeopathic treatments influences the effectiveness of ultra-high-diluted (UHD) arsenic trioxide at the 45th decimal dilution/dynamization (As2O3 45x). DESIGN: Wheat seeds, previously stressed with ponderal As2O3, were treated with: As2O3 45x, H2O 45x (dynamized control), or pure water (negative control). The succussion was done manually, and various succussion durations (numbers of strokes) were tested for each treatment. Treatment effectiveness was tested blind using the in vitro germination test and the droplet evaporation method (DEM). Data were processed by the Poisson test (germination test) and by two-way analysis of variance (DEM). MAIN OUTCOME MEASURES: We evaluated both the in vitro germination rate, by counting the non-germinated seeds, and the complexity of polycrystalline structures (PCS) (local connected fractal dimension (LCFD)) obtained by evaporating leakage droplets from stressed seeds that had been watered with the different treatments. RESULTS: We observed a highly significant increase in germination rate when the number of strokes (NS) was ≥32 for both As2O3 45x and H2O 45x, and a significant increase in the LCFD of PCS for As2O3 45x when the NS was ≥32 and for H2O 45x when it was 70. CONCLUSIONS: Both experimental approaches showed increased effectiveness for treatments prepared with a higher number of succussion strokes. These results indicate that succussion may have an important influence on treatment effectiveness, and so highlight the need for further research.

Structural and thermal analyses of zinc and lactose in homeopathic triturated systems.

BACKGROUND: A series of different experimental approaches was applied in Zincum metallicum (Zinc met.) samples and lactose controls. Experiments were designed to elucidate the effect of zinc trituration and dynamization on physicochemical properties of homeopathic formulations, using lactose as excipient. METHODS: Zinc met. potencies (Zinc met 1-3c) were triturated and dynamized using lactose as excipient, according to Brazilian Homeopathic Pharmacopoeia. Lactose samples (LAC 1-3c) were also prepared following the same protocol and used as controls. The samples were analyzed structurally by Atomic Absorption Spectroscopy (AAS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) with Energy Dispersive X-ray Spectroscopy (EDX) and Scanning Electron Microscopy (SEM), and thermodynamically by Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC). RESULTS: AAS analysis detected 97.0 % of zinc in the raw material, 0.75 % (Zinc met 1c) and 0.02% (Zinc met 2c). XRD analysis showed that inter-atomic crystalline spacing of lactose was not modified by dynamization. Amorphous and crystalline lactose spheres and particles, respectively, were observed by TEM in all samples, with mean size from 200 to 800 nm. EDX obtained with TEM identified zinc presence throughout the amorphous matter but individualized zinc particles were not observed. SEM images obtained from dynamized samples (LAC 1c and Zinc met 1c) with electron backscattering could not identify zinc metal grains. The dynamization process induced Derivatives of Thermal Gravimetric (DTg) peak modification, which was previously centered near 158°C to lactose, to a range from 140 to 170°C, suggesting the dynamization process modifies the temperature range of water aggregation. Thermal phenomena were analyzed and visualized by Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) statistics. Both indicated that fusion enthalpy of dynamized samples (DynLAC 1-3c; DynZn 1-3c) increased 30.68 J/g in comparison to non-dynamized lactose (LAC; p < 0.05). CONCLUSIONS: Our results suggested no structural changes due to the trituration and dynamization process. However, TG and DSC analyses permit the differentiation of dynamized and non-dynamized groups, suggesting the dynamization process induced a significant increase in the degradation heat. These results call for further calorimetric studies with other homeopathic dilutions and other methodologies, to better understand the dynamics of these systems.

Effectiveness and Safety of Arnica montana in Post-Surgical Setting, Pain and Inflammation.

Arnica montana has been widely used as a homeopathic remedy for the treatment of several inflammatory conditions in pain management and postoperative settings. This review gives an overview of the therapeutic use of Arnica montana in the above-mentioned fields also focusing on its mechanisms of action learned from animal models and in vitro studies. Arnica montana is more effective than placebo when used for the treatment of several conditions including post-traumatic and postoperative pain, edema, and ecchymosis. However, its dosages and preparations used have produced substantial differences in the clinical outcome. Cumulative evidence suggests that Arnica montana may represent a valid alternative to non-steroidal anti-inflammatory drugs, at least when treating some specific conditions.

Arnica montana effects on gene expression in a human macrophage cell line. Evaluation by quantitative Real-Time PCR.

BACKGROUND: Arnica montana is a popular traditional remedy widely used in complementary medicine, also for its wound healing properties. Despite its acknowledged action in clinical settings at various doses, the molecular aspects relating to how A. montana promotes wound healing remain to be elucidated. To fill this gap, we evaluated the whole plant extract, in a wide range of dilutions, in THP-1 human cells, differentiated into mature macrophages and into an alternative IL-4-activated phenotype involved in tissue remodelling and healing. METHODS: Real-time quantitative Reverse Transcription Polymerase Chain Reaction (PCR) analysis was used to study the changes in the expression of a customized panel of key genes, mainly cytokines, receptors and transcription factors. RESULTS: On macrophages differentiated towards the wound healing phenotype, A. montana affected the expression of several genes. In particular CXC chemokine ligand 1 (CXCL1), coding for an chief chemokine, exhibited the most consistent increase of expression, while also CXC chemokine ligand 2 (CXCL2), Interleukin8 (IL8) and bone morphogenetic protein (BMP2) were slightly up-regulated, suggesting a positive influence of A. montana on neutrophil recruitment and on angiogenesis. MMP1, coding for a metalloproteinase capable of cleaving extracellular matrix substrates, was down-regulated. Most results showed non-linearity of the dose-effect relationship. CONCLUSIONS: This exploratory study provides new insights into the cellular and molecular mechanisms of action of A. montana as a promoter of healing, since some of the genes it modifies are key regulators of tissue remodelling, inflammation and chemotaxis.

Immunological models in high dilution research following M Bastide.

In 1994, Madeleine Bastide described experimental models in immunology that were used during the 1980s to investigate high dilution effects on several biological systems. She classified the available papers in four categories: High dilutions of antigens; High dilutions of thymus, bursa and other hormones; High dilutions of cytokines; Immunopharmacological activity of silica. The studies about high dilutions of antigens were not continued after this period, but gave rise to a long process of a series of in vitro models on antigens and histamine dilutions, that led to the demonstration of the biological modulation effects of these preparations on basophil degranulation. During this process, a multi-centre study was performed, with a high degree of reproducibility among different independent laboratories. The studies about high diluted cytokines, thymulin and other hormones opened a new line of scientific investigation, about the regulatory properties of endogenous substances prepared according to homeopathic methods. The most frequently studied substance, thymulin, when administered to mice at 5cH potency, is able to improve the activity of phagocytes in different experimental situations, such as viral, bacterial and parasitic infections. The immunopharmacological activity of silica was demonstrated, at that time, as an in vivo illustration of the homeopathic 'similia principle'. More recently, studies on silica have assumed another focus: the putative role of silica as active contaminant present in high dilutions. This paper presents a follow-up summary on these items, considering the evolution of discoveries from 1994 to 2014.

Replications of fundamental research models in ultra high dilutions 1994 and 2015--update on a bibliometric study.

INTRODUCTION: This paper focuses exclusively on experimental models with ultra high dilutions (i.e. beyond 10(-23)) that have been submitted to replication scrutiny. It updates previous surveys, considers suggestions made by the research community and compares the state of replication in 1994 with that in 2015. METHODS: Following literature research, biochemical, immunological, botanical, cell biological and zoological studies on ultra high dilutions (potencies) were included. Reports were grouped into initial studies, laboratory-internal, multicentre and external replications. Repetition could yield either comparable, or zero, or opposite results. The null-hypothesis was that test and control groups would not be distinguishable (zero effect). RESULTS: A total of 126 studies were found. From these, 28 were initial studies. When all 98 replicative studies were considered, 70.4% (i.e. 69) reported a result comparable to that of the initial study, 20.4% (20) zero effect and 9.2% (9) an opposite result. Both for the studies until 1994 and the studies 1995-2015 the null-hypothesis (dominance of zero results) should be rejected. Furthermore, the odds of finding a comparable result are generally higher than of finding an opposite result. Although this is true for all three types of replication studies, the fraction of comparable studies diminishes from laboratory-internal (total 82.9%) to multicentre (total 75%) to external (total 48.3%), while the fraction of opposite results was 4.9%, 10.7% and 13.8%. Furthermore, it became obvious that the probability of an external replication producing comparable results is bigger for models that had already been further scrutinized by the initial researchers. CONCLUSIONS: We found 28 experimental models which underwent replication. In total, 24 models were replicated with comparable results, 12 models with zero effect, and 6 models with opposite results. Five models were externally reproduced with comparable results. We encourage further replications of studies in order to learn more about the model systems used.

Cell sensitivity, non-linearity and inverse effects.

It has been claimed that the homeopathic principle of 'similarity' (or 'similia') and the use of individualized remedies in extremely low doses conflicts with scientific laws, but this opinion can be disputed on the basis of recent scientific advances. Several mechanisms to explain the responsiveness of cells to ultra-low doses and the similarity as inversion of drug effects, have again been suggested in the framework of hormesis and modern paradoxical pharmacology. Low doses or high dilutions of a drug interact only with the enhanced sensitivities of regulatory systems, functioning as minute harmful stimuli to trigger specific compensatory healing reactions. Here we review hypotheses about homeopathic drug action at cellular and molecular levels, and present a new conceptual model of the principle of similarity based on allosteric drug action. While many common drugs act through orthostatic chemical interactions aimed at blocking undesired activities of enzymes or receptors, allosteric interactions are associated with dynamic conformational changes and functional transitions in target proteins, which enhance or inhibit specific cellular actions in normal or disease states. The concept of allostery and the way it controls physiological activities can be broadened to include diluted/dynamized compounds, and may constitute a working hypothesis for the study of molecular mechanisms underlying the inversion of drug effects.

Extreme sensitivity of gene expression in human SH-SY5Y neurocytes to ultra-low doses of Gelsemium sempervirens.

BACKGROUND: Gelsemium sempervirens L. (Gelsemium s.) is a traditional medicinal plant, employed as an anxiolytic at ultra-low doses and animal models recently confirmed this activity. However the mechanisms by which it might operate on the nervous system are largely unknown. This work investigates the gene expression of a human neurocyte cell line treated with increasing dilutions of Gelsemium s. extract. METHODS: Starting from the crude extract, six 100 × (centesimal, c) dilutions of Gelsemium s. (2c, 3c, 4c, 5c, 9c and 30c) were prepared according to the French homeopathic pharmacopoeia. Human SH-SY5Y neuroblastoma cells were exposed for 24 h to test dilutions, and their transcriptome compared by microarray to that of cells treated with control vehicle solutions. RESULTS: Exposure to the Gelsemium s. 2c dilution (the highest dose employed, corresponding to a gelsemine concentration of 6.5 × 10(-9) M) significantly changed the expression of 56 genes, of which 49 were down-regulated and 7 were overexpressed. Several of the down-regulated genes belonged to G-protein coupled receptor signaling pathways, calcium homeostasis, inflammatory response and neuropeptide receptors. Fisher exact test, applied to the group of 49 genes down-regulated by Gelsemium s. 2c, showed that the direction of effects was significantly maintained across the treatment with high homeopathic dilutions, even though the size of the differences was distributed in a small range. CONCLUSIONS: The study shows that Gelsemium s., a medicinal plant used in traditional remedies and homeopathy, modulates a series of genes involved in neuronal function. A small, but statistically significant, response was detected even to very low doses/high dilutions (up to 30c), indicating that the human neurocyte genome is extremely sensitive to this regulation.

High-dilution effects revisited. 1. Physicochemical aspects.

Several lines of evidence suggest that homeopathic high dilutions (HDs) can effectively have a pharmacological action, and so cannot be considered merely placebos. However, until now there has been no unified explanation for these observations within the dominant paradigm of the dose-response effect. Here the possible scenarios for the physicochemical nature of HDs are reviewed. A number of theoretical and experimental approaches, including quantum physics, conductometric and spectroscopic measurements, thermoluminescence, and model simulations investigated the peculiar features of diluted/succussed solutions. The heterogeneous composition of water could be affected by interactive phenomena such as coherence, epitaxy and formation of colloidal nanobubbles containing gaseous inclusions of oxygen, nitrogen, carbon dioxide, silica and, possibly, the original material of the remedy. It is likely that the molecules of active substance act as nucleation centres, amplifying the formation of supramolecular structures and imparting order to the solvent. Three major models for how this happens are currently being investigated: the water clusters or clathrates, the coherent domains postulated by quantum electrodynamics, and the formation of nanoparticles from the original solute plus solvent components. Other theoretical approaches based on quantum entanglement and on fractal-type self-organization of water clusters are more speculative and hypothetical. The problem of the physicochemical nature of HDs is still far from to be clarified but current evidence strongly supports the notion that the structuring of water and its solutes at the nanoscale can play a key role.

High-dilution effects revisited. 2. Pharmacodynamic mechanisms.

The pharmacodynamics aspects of homeopathic remedies are appraised by laboratory studies on the biological effects at various levels (cellular, molecular and systemic). The major question is how these medicines may work in the body. The possible answers concern the identification of biological targets, the means of drug-receptor interactions, the mechanisms of signal transmission and amplification, and the models of inversion of effects according to the traditional 'simile' rule. These problems are handled by two experimental and theoretical lines, according to the doses or dilutions considered (low-medium versus high dilutions). Homeopathic formulations in low-medium dilutions, containing molecules in the range of ultra-low doses, exploit the extreme sensitivity of biological systems to exogenous and endogenous signals. Their effects are interpreted in the framework of hormesis theories and paradoxical pharmacology. The hypotheses regarding the action mechanisms of highly diluted/dynamized solutions (beyond Avogadro-Loschmidt limit) variously invoke sensitivity to bioelectromagnetic information, participation of water chains in signalling, and regulation of bifurcation points of systemic networks. High-dilution pharmacology is emerging as a pioneering subject in the domain of nanomedicine and is providing greater plausibility to the puzzling claims of homeopathy.

Basic research in homeopathy and ultra-high dilutions: what progress is being made?

This report summarises the latest research developments in the field of high dilutions and homeopathy, as presented at the GIRI symposium of the leading international organisation of scientists in this field, in Florence, Italy in September 2012. The scientific community's early scepticism concerning the possible biological and pharmacological activity of highly diluted solutions, is giving way to a more open-minded attitude that no longer obstructs critical and experimental investigations in this emerging field of biomedicine.

Testing homeopathy in mouse emotional response models: pooled data analysis of two series of studies.

Two previous investigations were performed to assess the activity of Gelsemium sempervirens (Gelsemium s.) in mice, using emotional response models. These two series are pooled and analysed here. Gelsemium s. in various homeopathic centesimal dilutions/dynamizations (4C, 5C, 7C, 9C, and 30C), a placebo (solvent vehicle), and the reference drugs diazepam (1 mg/kg body weight) or buspirone (5 mg/kg body weight) were delivered intraperitoneally to groups of albino CD1 mice, and their effects on animal behaviour were assessed by the light-dark (LD) choice test and the open-field (OF) exploration test. Up to 14 separate replications were carried out in fully blind and randomised conditions. Pooled analysis demonstrated highly significant effects of Gelsemium s. 5C, 7C, and 30C on the OF parameter "time spent in central area" and of Gelsemium s. 5C, 9C, and 30C on the LD parameters "time spent in lit area" and "number of light-dark transitions," without any sedative action or adverse effects on locomotion. This pooled data analysis confirms and reinforces the evidence that Gelsemium s. regulates emotional responses and behaviour of laboratory mice in a nonlinear fashion with dilution/dynamization.

On the plausibility of homeopathic 'similitude'.

The homeopathic principle of similitude is not based on the principle of vaccination but on the more general principle of inversion of effects, a widespread medical phenomenon. Based on the systemic networks which play an important role in response to stress, this principle concerns the reorganization of regulation systems, through a coherent response to the medicine. This model is backed by a large number of published studies from our laboratory and others, by toxicological evidence such as the emerging fields of 'hormesis', of neuropharmacology, and of systems biology. The immune system is just one example of the possible application of this law of similitude, which constitutes the true 'heart' of the homeopathic idea, and again ethically justifies the attempt to apply it to experimental pharmacology.

Effects of Ignatia amara in mouse behavioural models.

BACKGROUND: Ignatia amara (Ignatia), a remedy made from the Strychnos ignatii seeds, is used for anxiety-related symptoms, but consistent evidence of its activity in reproducible experimental models is lacking. An investigation was performed in order to assess on mice, by means of emotional response models, the activity of homeopathic Ignatia dilutions/dynamizations. METHODS: Groups of 8 mice of the CD1 albino strain were treated intraperitoneally for 9 days with 0.3ml of five centesimal (C) dilutions/dynamizations of Ignatia (4C, 5C, 7C, 9C and 30C). Control mice were treated with the same hydroalcoholic (0.3%) solution used to dilute the medicines. Diazepam (1mg/kg) was the positive reference drug. Validated test models for locomotion and emotional response, the Open-Field (OF) and the Light-Dark (LD) tests, were employed. Five replications of the same protocol were carried out, in a randomised way using coded drugs/controls. RESULTS: In the OF the general locomotion of mice was slightly decreased by Ignatia 4C, but not by Ignatia 5C, 7C, 9C and 30C, indicating the absence of unspecific motor impairment or sedation by these dilutions/dynamizations. Ignatia and diazepam seemed to decrease the number of urine spots released in the OF during 10min, with borderline significance (P=0.083). In the LD the tested medicine showed anxiolytic-like activity (increase of time spent and distance travelled in the lit area), though to a lesser extent than diazepam. The highest and most significant difference with untreated controls (P<0.01) was observed with the 9C dilution/dynamization. Among the 5 replication experiments, the best drug effects were obtained where the baseline anxiety of mice was higher. CONCLUSIONS: Homeopathic Ignatia dilutions/dynamizations (peak at 9C) modify some emotion-related symptoms in laboratory mice without affecting locomotion.

Homeopathic Doses of Gelsemium sempervirens Improve the Behavior of Mice in Response to Novel Environments.

Gelsemium sempervirens is used in homeopathy for treating patients with anxiety related symptoms, however there have been few experimental studies evaluating its pharmacological activity. We have investigated the effects of homeopathic doses of G. sempervirens on mice, using validated behavioral models. Centesimal (CH) dilutions/dynamizations of G. sempervirens, the reference drug diazepam (1 mg/kg body weight) or a placebo (solvent vehicle) were intraperitoneally delivered to groups of mice of CD1 strain during 8 days, then the effects were assessed by the Light-Dark (LD) choice test and by the Open-Field (OF) exploration test, in a fully blind manner. In the LD test, the mean time spent in the illuminated area by control and placebo-treated animals was 15.98%, for mice treated with diazepam it increased to 19.91% (P = .047), while with G. sempervirens 5 CH it was 18.11% (P = .341, non-significant). The number of transitions between the two compartments increased with diazepam from 6.19 to 9.64 (P < .001) but not with G. Sempervirens. In the OF test, G. sempervirens 5 CH significantly increased the time spent and the distance traveled in the central zone (P = .009 and P = .003, resp.), while diazepam had no effect on these OF test parameters. In a subsequent series of experiments, G. sempervirens 7 and 30 CH also significantly improved the behavioral responses of mice in the OF test (P < .01 for all tested variables). Neither dilutions of G. sempervirens affected the total distance traveled, indicating that the behavioral effect was not due to unspecific changes in locomotor activity. In conclusion, homeopathic doses of G. sempervirens influence the emotional responses of mice to novel environments, suggesting an improvement in exploratory behavior and a diminution of thigmotaxis or neophobia.