Clinical Effect of the Traditional Japanese Herbal Medicine "Goreisan" on Water Balance in Patients With Severe Acute Pancreatitis.

BACKGROUND: Since severe acute pancreatitis (SAP) involves inflammatory mediators produced by local inflammation of the pancreas that trigger a systemic inflammatory response, intensive fluid management is required to maintain hemodynamics in the early stages of the onset of SAP. Goreisan is considered to have a diuretic effect in a state of excess water and an antidiuretic effect in a state of dehydration, regulating water balance in both directions. We investigated the clinical effects of Goreisan on water balance in SAP patients. Patients and methods: SAP patients admitted to our ICU within 72 hours of being diagnosed with SAP were divided into two groups: the Rikkunshito group (before October 2015) and the Goreisan group (after November 2015). Cumulative volume of fluid infusion, urine, fluid removal by CHF, nasogastric tube drainage, and water balance from day 1 to day 5 of ICU admission. RESULTS: Thirty patients were included. The median age was 57 (40-69) years, and 21/30 (70%) were male. The prognostic factor score in Japanese criteria for acute pancreatitis was 5.5 (3.3-7). Of the thirty patients, 14 were in the Rikkunshito group, and 16 were in the Goreisan group. There were no differences in the cumulative volume of fluid infusion, urine, fluid removal by CHF, or nasogastric tube drainage from day 1 to day 5 of ICU admission between the two groups. However, the cumulative water balance from day 1 to day 5 of admission was 4,957 ± 6,091 mL in the Rikkunshito group, whereas it was lower in the Goreisan group at 498 ± 3,918 mL (P = 0.023). CONCLUSION: Our study showed that Goreisan administration in patients with severe acute pancreatitis might improve water balance in the early phase of onset. Early administration of Goreisan at the onset of severe acute pancreatitis may regulate fluid movement between capillaries and interstitium and alleviate fluid overload due to water refill.

Effectiveness of traditional herbal Kampo medicine Goreisan on chronic subdural hematoma recurrence: a meta-analysis.

Objectives: Our objective was to compare the effectiveness of Traditional Chinese herbal Kampo medicine Goreisan in improving recurrence in patients with chronic subdural hematoma (CSDH). Methods: Eligible randomized controlled trials prospective trials, and retrospective cohort studies were systematically identified through searches of PubMed, Cochrane Library, and CNKI from inception to March 2024. Following the application of predetermined inclusion and exclusion criteria to screen the available studies, main outcome measures were rigorously extracted. RevMan v5.4 software was utilized to evaluate the overall recurrence rate, employing a random-effects model to calculate pooled odds ratios with the Mantel-Haenszel estimation method. Inter-study heterogeneity was assessed using the Cochran Q (Chi-square) test and I2 statistics. Funnel plots were used to evaluate publication bias. Results: Among the 48 articles initially screened for citation, eight were ultimately selected for inclusion in the study. The results of our network meta-analysis indicate that patients with newly diagnosed Chronic subdural hematoma experienced a significantly reduced recurrence rate when treated with Goreisan compared to standard neurosurgical treatment (OR: 0.72; 95% CI 0.61-0.86; p = 0.00003). There was no statistically significant difference in the incidence rates of complications, including general fatigue, allergic reactions, hepatic dysfunction, and interstitial pneumonia (OR: 7.21; 95% CI 0.37-141.29; p = 0.19). Conclusion: Traditional medicine Goreisan was effective in reducing CDSH recurrence rates. For clinical treatment, it provides a high level of evidence-based medicine. It is also necessary to conduct multicenter randomized controlled trials with dose adjustments to determine whether Goreisan interventions improve neurological function or prognosis.

Effect of Goreisan, a Traditional Japanese Medicine, on Rat Hindlimb Lymphedema.

Secondary lymphedema occurs after cancer surgery involving lymph node dissection owing to the lymphatic system dysfunction. However, the pathophysiology of lymphedema and the molecular pathways involved remain unknown. This study aimed to develop a rat hindlimb lymphedema model and investigate the mechanisms that drive pathophysiology and the effects of the traditional Japanese medicine goreisan on lymphedema. The rat lymphedema model was induced by combination surgeries of popliteal lymph node dissection, skin cautery incision, and fascial ablation coagulation in the right hindlimb using male Wistar rats. The foot volume was significantly increased, and recovery was delayed by combination surgeries. Dermal thickness and dilated lymphatic vessels of the hindlimb were observed on postoperative day 2. The number of infiltrating leukocytes (CD45+ cells), including CD4+ T-cells, increased in the lymphedema group compared with that in the sham group. The relative mRNA expression and protein levels of interleukin-6 (IL-6), CC chemokine ligand 2 (CCL2), transforming growth factor ß1 (TGF-ß1), and Fms-related receptor tyrosine kinase 4 (FLT4) were significantly higher in the lymphedema group than in the sham group. Foot volume was decreased by goreisan, furosemide, and prednisolone treatments. Goreisan diminished the increase in CD4+ T-cells, and the same trend was observed for CCL2 and FLT4 expression. In conclusion, the rat hindlimb lymphedema model in this study exhibited increased foot volume, skin-infiltrating cells, and pathological changes accompanied by inflammatory and fibrotic responses, suggesting that the model presented significant clinical features of lymphedema. Goreisan may exert a therapeutic effect on lymphedema by inhibiting CD4+ T-cell infiltration.

Goreisan regulates cerebral blood flow according to barometric pressure fluctuations in female C57BL/6J mice.

Goreisan is a Kampo medicine used to treat headaches associated with climate change. Here, by using an implantable complementary metal-oxide-semiconductor (CMOS) device, we evaluated the effects of Goreisan and loxoprofen on cerebral blood flow (CBF) dynamics associated with barometric pressure fluctuations in freely moving mice. In the vehicle group, decreasing barometric pressure increased CBF that was prevented by Goreisan and loxoprofen. Notably, Goreisan, but not loxoprofen, reduced CBF after returning to atmospheric pressure. These results indicate that, unlike the mechanism of action of antipyretic analgesics, Goreisan normalizes CBF abnormalities associated with barometric pressure fluctuations by actively reducing CBF increase.

A Case of Refractory Cancer-related Neuropathic-pain Caused by Intracranial Invasion of Left Nasal Cavity Carcinoma Successfully Treated with Goreisan

Introduction: Intracranial tumors cause various neurological symptoms and neuropathic pain, which are often refractory to opioids. In some of these cases, the combination of Kampo medicines can be effective. Case: The case was a 44-year-old patient who underwent surgery for a suspected papilloma. After resection, pathological examination revealed squamous cell carcinoma, positive for margins, and then, the left intraorbital metastasis was observed. Due to the intracranial invasion of the tumor, he had pain in the second and third branches of the trigeminal nerve in the left face and paresthesia in the second branch of the trigeminal nerve bilaterally (Numerical Rating Scale: NRS 10/10). Hydromorphone was introduced, and the pain was relieved, but the paresthesia remained (NRS 8/10). Both paresthesia and pain worsened during the course of chemotherapy, but MRI showed no tumor progression, thus, the cause of symptom aggravation was diagnosed edema of the tissue around the tumor. Therefore, Goreisan was started, and both paresthesia and pain were relieved. Discussion: Goreisan has been shown to be effective in cerebral edema due to its water-regulating effect by inhibiting aquaporin. In the present case, the reduction of edema in peritumoral tissues by Goreisan may have contributed to the symptomatic relief.

TJ-17 (Goreisan) mitigates renal fibrosis in a mouse model of folic acid-induced chronic kidney disease.

BACKGROUND AND PURPOSE: TJ-17 (Goreisan), a traditional Japanese Kampo medicine, has been generally used to treat edema, such as heart failure, due to its diuretic effect. In the present study, we investigate the effects of TJ-17 on chronic kidney disease (CKD). METHODS: We the preventive action of TJ-17 against acute kidney injury (AKI) transition to CKD in vivo using a folic acid (FA)-induced mouse model. Mice were treated with food containing TJ-17 at 48 h after FA intraperitoneal injection (AKI phase). RESULTS: Histological analysis, as well as renal function and renal injury markers, deteriorated in mice with FA-induced CKD and were ameliorated by TJ-17 treatment. Increased levels of inflammatory cytokines and macrophage infiltration were also alleviated in mice treated with TJ-17. Renal fibrosis, a crucial factor in CKD, was induced by FA administration and inhibited by TJ-17 treatment. Pretreatment with TJ-17 did not exert an inhibitory effect on FA-induced AKI. The increase in urinary volume in FA-induced CKD mice was ameliorated by TJ-17 treatment, with a concurrent correction of reduced aquaporins expression in the kidney. CONCLUSION: TJ-17 may have a novel preventive effect against inflammation, oxidative stress, and fibrosis, contributing to innovation in the treatment of CKD.

Conservative Treatment of Chronic Subdural Hematoma with Gorei-san.

Most asymptomatic patients with chronic subdural hematoma (CSDH) are followed conservatively but can require surgical treatment if the hematoma expands. We conducted a retrospective evaluation of the effect of Gorei-san on CSDH. This study included patients treated between April 2013 and March 2015. In total, 289 patients were diagnosed with CSDH and 110 patients received conservative management. Finally, 39 patients who met the requirements were registered. We retrospectively examined the age, gender, medical history, hematoma thickness, clarity of sulci below hematomas, and midline shift of the patients. The primary outcome was the median surgery-free interval, and the secondary results were the rate of CSDH shrinkage and surgery avoidance. A comparison of patient characteristics between the Gorei-san (G) and non-Gorei-san (NG) groups found no significant differences in the percentage of men, average ages, past history, thickness of CSDH (15.0 ± 3.1 mm vs. 15.3 ± 2.6 mm, p = 0.801), or midline shift (2.0 ± 2.7 mm vs. 4.0 ± 5.0 mm, p = 0.230). The median surgery-free interval was significantly different between the G and NG groups [n. r. vs. 41 days (95% CI: 5-79), log-rank p = 0.047]. The CSDH avoidance rate was not significantly different between the two groups (70.0% vs. 34.4%, p = 0.071). Additionally, the CSDH shrinkage rate was significantly different between the two groups (60.0% vs. 10.3%, p = 0.004). This retrospective study demonstrated that CSDH treatment with Gorei-san reduces hematoma significantly more than treatment that does not include Gorei-san.

Impact of Goreisan components on rat mesenteric collecting lymphatic vessel pumping.

BACKGROUND: Goreisan is a traditional herbal formulation with diuretic properties tested as a clinical therapeutic to alleviate lymphedema in Japan. The present study aimed to determine how Goreisan and its five different components affect lymphatic pump function. METHODS: Mesenteric collecting lymphatics were isolated from anesthetized Sprague-Dawley rats and mounted on resistance-matched glass micropipettes in a 37°C physiological salt solution bath for studies. Diameter was continuously measured to obtain the following lymphatic pump parameters: contraction frequency (CF), end diastolic diameter (EDD), and end systolic diameter (ESD), contraction amplitude (AMP), ejection fraction (EF), and fractional pump flow (FPF). Goreisan and each of its components (Cinnamomi Cortex, Atractylodis Rhizoma, Alismatis Rhizoma, Polyporus, and Poria) were applied to the bath at concentrations of 1-30 µg/mL. RESULTS: The results show that while Goreisan causes no significant changes to lymphatic pumping, Alismatis Rhizoma and Polyporus each significantly reduce CF and FPF. In addition, rats that received oral administration of Goreisan and Alismatis Rhizoma for 1 week had elevated expression of VEGFR-3 in their mesenteric collecting lymphatics. CONCLUSIONS: Collectively, the results suggest that some components of Goreisan have a direct, rapid impact on lymphatic pumping. These findings provide new insights but also raise new questions about the therapeutic potential of Goreisan in patients with secondary lymphedema.

Investigation on Headache Caused by Weather and Atmospheric Pressure Changes and Use of Goreisan / 社会薬学

A questionnaire survey was conducted to investigate the use of goreisan for headaches caused by weather and atmospheric pressure changes, and to clarify issues in promoting treatment with goreisan. The subjects were men and women in their 20s to 40s who developed headaches due to changes in weather and atmospheric pressure. Medication was used by 58.0% of the migraine group and 42.5% of the other headaches group. Among them, 27.5% of the migraine group and 15.1% of the other headaches group had used goreisan. Regarding the method of use of goreisan, the most common answer for the migraine group was “used after feeling a sign that headache is likely to occur,” whereas for the other headaches group, the most common response was “used after headache has occurred.” In the migraine group, the most frequent premonitory symptom was “stiffness in the shoulders and neck.” More than 80% of both groups were satisfied with the use of goreisan. In addition, 77.8% of migraine group and 59.5% of the other headaches group of those who had never used goreisan answered that they would like to use goreisan for headaches caused by weather or atmospheric pressure changes in the future. As a reason for not wanting to use goreisan, over half of both groups answered that they did not like the taste of herbal medicines. It is necessary to offer tablets to patients that do not like the taste.

Effect of Goreisan, a Japanese Traditional Medicine, on Cortical Spreading Depolarization in Mice.

Goreisan, a traditional Japanese Kampo medicine, is often used to treat headaches, including migraines; however, the underlying mechanisms remain unknown. Therefore, we investigated whether chronic treatment with Goreisan affects cortical spreading depolarization (CSD) in migraines. CSD susceptibility was assessed in male and female C57BL/6 mice by comparing CSD threshold, propagation velocity, and CSD frequency between animals treated with Goreisan for approximately 3 weeks and the corresponding controls with a potassium-induced CSD model. No significant differences were observed in CSD susceptibility between mice that were chronically treated with Goreisan and the control mice. Additionally, no significant differences were observed in other physiological parameters, including body weight, blood gases, and blood pressure. CSD susceptibility was not affected by chronic treatment with Goreisan, which suggests that the drug treats headaches via mechanisms that do not involve CSD modulation.

Japanese herbal Kampo medicine, Keishibukuryogan, for chronic subdural hematoma - Prospective observational study.

Background: Pharmacological treatment for chronic subdural hematoma (CSDH) recurrence prevention after surgery is under debate. CSDH may be related to suidoku (fluid disturbance) from the Japanese herbal kampo perspective. Goreisan (GRS) treats suidoku and is used to prevent a postoperative recurrence. However, not all CSDHs are liquid, and some have structures such as trabecula, hematoma, and clots, suggesting oketsu (blood stasis). Therefore, we prospectively investigated the keishibukuryogan (KBG) effectiveness, which treats oketsu, for CSDH recurrence prevention and hematoma resolution compared to GRS. Methods: We prospectively prescribed KBG 7.5 g/day for 12 CSDH patients after burr-hole surgery. As a control cohort, we retrospectively collected 48 patients treated by GRS 7.5 g/day. The recurrence within 1 month and the hematoma thickness after 1 month were evaluated. Results: The median age was 84 years old. All the patients' symptoms improved after surgery. The median preoperative midline shift and mean hematoma thicknesses were 6.0 mm and 23.75 mm. Those at 1 month were 2.0 mm and 11.43 mm. The recurrence rate was not significantly different between the KBG cohort (1 of 12) and the GRS cohort (4 of 48) (P = 0.999). The KBG's noninferiority to GRS regarding the hematoma thickness at 1 month was statistically proven; KBG (12.26 mm) and GRS (11.20 mm). Conclusion: The recurrence rate at 1 month was not different between the KBG and GRS cohorts. The hematoma thickness at 1 month in the KBG cohort was not statistically inferior to that in the GRS cohort.

In vitro assessment of the inhibitory effect of goreisan extract and its ingredients on the P-glycoprotein drug transporter and cytochrome P-450 metabolic enzymes.

Kampo medicines are widely used in Japan; however, their potential to cause drug interactions still remains unclear and needs to be further investigated. The effects of goreisan on the P-glycoprotein (P-gp) and the cytochrome P-450 (CYP), which are associated with drug interactions, were investigated.The inhibitory effect of goreisan extract on P-gp was evaluated using a Caco-2 cell permeability assay. The results indicated that it inhibited P-gp function in a concentration-dependent manner.The inhibitory effect of three goreisan ingredients (alisol A, tumulosic acid, and (E)-cinnamic acid) on seven CYP isoforms was evaluated using human liver microsomes (HLM). Of these, tumulosic acid and (E)-cinnamic acid exhibited less than 16% inhibition at concentrations of 10 µmol/L against any of the CYP isoforms tested. Alisol A inhibited only CYP3A but showed no inhibitory effect with pre-incubation.These results indicate that goreisan extract has inhibitory activity against P-gp and that alisol A, a goreisan ingredient, exhibits an inhibitory effect on CYP3A. However, these are thought to be minor or negligible in vivo. Overall, these findings will be useful to evaluate possible drug interactions and provide support for the interpretation of future clinical drug-drug interaction studies involving goreisan.

Spontaneous Intracranial Hypotension Manifesting Orthostatic Headache Worsened by Playing the Saxophone and Treated by Japanese Herbal Kampo Medicine Goreisan.

We present a 15-year-old Japanese girl with no previous medical history who presented with a gradually worsening series of orthostatic headaches. We diagnosed spontaneous intracranial hypotension, worsened by playing the saxophone and its Valsalva maneuver effect. She was treated with Japanese herbal Kampo medicine Goreisan 7.5 g/day in three divided doses, and her symptoms gradually improved. Her headache has never recurred for a year when she played the saxophone. Our case's headache may have been further exacerbated by cerebrospinal fluid (CSF) leakage due to CSF pressure increase by Valsalva maneuvers while playing the saxophone. Our case suggested that the Japanese herbal Kampo medicine Goreisan can facilitate the glymphatic system and adjust the CSF pressure appropriately.

The Efficacy of Japanese Herbal Kampo Medicine as an Acute and Prophylactic Medication to Treat Chronic Daily Headache and Medication Overuse Headache:-Single Arm Retrospective Study.

Introduction A chronic daily headache (CDH) comprises a group of headaches occurring at least 15 days per month for three or more consecutive months. We retrospectively investigated the effectiveness of the hybrid treatment strategy for CDH using Kampo medicine combined with Western medication. Methods We retrospectively investigated 43 consecutive first-visit CDH patients. In addition to Western acute and prophylactic medications, we prescribed three types of Kampo medicines: goreisan, goshuyuto, and kakkonto depending on the patients' symptoms. Headache impact test-6 (HIT-6), monthly headache days (MHD), monthly migraine days (MMD), and monthly acute medication intake days (AMD) before, 1- and 3-months after starting the hybrid medications were assessed as outcomes. Results Thirty-six women and seven men were included. The median age was 51 years old. Nine were chronic migraine (CM), 22 were episodic migraine and tension-type headaches (EM+TTH), and 12 were chronic TTH. Twenty-seven patients also had medication overuse headaches (MOH). The medians of HIT-6 before, one and three months after treatment were 63, 48, and 40, respectively. Those of MHD were 20, 5, and 2. Those of MMD were 2, 0, and 0. Those of AMD were 15, 0, and 0. Significant reductions in HIT-6, MDH, MMD, and AMD were observed one and three months after starting Kampo treatment. Similar trends were observed in the EM+TTH and MOH patients as subgroup analyses. Conclusion The hybrid medication strategy of Kampo and Western medicines for CDH is safe and effective in terms of both acute and prophylactic medications with rapid efficacy.

Medication Overuse Headache Successfully Treated by Three Types of Japanese Herbal Kampo Medicine.

Medication overuse headache (MOH) usually resolves after the overuse is stopped and starting prophylactic medications. However, it can be challenging to prescribe common prophylactic medications when patients have a history of side effects. As an alternative therapy, traditional Japanese herbal kampo medicine can be used. We herein report a case of a MOH woman with a history of side effects by such common prophylactic medications. A 50-year-old woman presented with a severe migraine attack. She had suffered from migraines for 10 years. She had taken loxoprofen and sumatriptan every day for over eight years. As prophylactic medications, lomerizine, valproic acid, and amitriptyline had been prescribed in the past, but they were discontinued due to side effects. Therefore, she could continue only propranolol as prophylactic medication. She had severe pulsatile headaches and nausea every day. We diagnosed triptan- and non-steroidal anti-inflammatory drug-overuse headache (the International Classification of Headache Disorders 3rd edition code 8.2.2 and 8.2.3.2) and chronic migraine (code 1.3). She was admitted and stopped loxoprofen and sumatriptan. We prescribed three types of Japanese herbal kampo medicines - kakkonto (TJ-1), goreisan (TJ-17), and goshuyuto (TJ-31). Her headache was relieved on day 5, and she was discharged on day 7. In the 40 days after discharge, she had only three times mild headaches with a numeric rating scale (NRS) of 2/10. She did not need any triptans nor anti-inflammatory drugs. We herein presented the MOH woman who was successfully treated using three types of kampo medicine. We should pay attention to their side effects, but kampo medicine may be useful for MOH treatment as acute and prophylactic medications for primary headaches.

A Prospective Randomized Study on the Preventive Effect of Japanese Herbal Kampo Medicine Goreisan for Recurrence of Chronic Subdural Hematoma.

Although the recurrence of chronic subdural hematoma (CSDH) after surgical treatment significantly affects the patients' quality of life, the recurrence rate has not improved in decades. Goreisan, a Japanese herbal Kampo medicine, promotes the hydragogue effect and has been empirically used in the treatment of CSDH in Japan. We conducted a prospective randomized study to investigate whether Goreisan treatment decreases the recurrence rate of CSDH. Between March 2013 and December 2018, a total of 224 patients who underwent initial burr hole surgery for CSDH were randomly assigned to receive Goreisan for 3 months (Group G) or no medication (Group N). The primary endpoint was symptomatic recurrence within 3 months postoperatively, and the secondary endpoint was complications, including the adverse effects of Goreisan. Of 224 randomized patients, 208 were included in the final analysis (104 in Group G and 104 in Group N). The overall recurrence rate was 9.1% (19/208). The recurrence rate of Group G was lower than that of Group N (5.8% vs 12.5%, P = 0.09), but the difference was not statistically significant. However, a significant preventive effect of Goreisan was found in 145 patients with high-risk computed tomography (CT) features, namely, homogeneous and separated types (5.6% vs 17.6%, P = 0.04). Although the present study did not prove the beneficial effect of Goreisan treatment, it suggested the importance of selecting patients with an increased risk of recurrence. A subset of patients whose hematoma showed homogeneous and separated patterns on CT image might benefit from Goreisan treatment.

A Case of Goreisan with hoketsuzai (Blood-Tonifying Formula) that was Remarkably Effective for Severe Malnutrition / 日本東洋医学雑誌

We report a case in which goreisan with hoketsuzai (blood-tonifying formula) was successful in the treatment of a marked nutritional disorder. A 17-year-old woman was screened for prominent emaciation of unknown cause. After the administration of goreisan, edema was reduced and her body weight increased. Subsequently, anemia improved and muscle mass increased with a combination of shimotsuto or sokeikakketsuto. It is possible that goreisan with hoketsuzai improved the water balance of the whole body including the digestive tract, and restored the digestive and absorptive function.

Two Cases of Great Occipital Neuralgia as Meteorological Pain Successfully Treated with Goreisan / 日本東洋医学雑誌

Painful orthopedic diseases are sometimes aggravated because of weather changes ; this is referred to as meteorological pain. We report two cases of great occipital neuralgia (GON) due to traffic accident in patients whose pain was aggravated by weather changes. Case 1 involved a 41-year-old woman who developed lumbago and cervical pain following a traffic accident. Two months after the accident, she had irregular occipital pain. Three months after the accident, a great typhoon occurred, and she suffered from severe occipital pain since that morning. She was diagnosed with GON as meteorological pain and was administered goreisan ; her occipital pain then improved. Case 2 involved a 31-year-old woman who developed cervical pain following a traffic accident. Three months after the accident, she experienced severe occipital pain due to weather changes. She was diagnosed with GON as meteorological pain and was administered goreisan ; her occipital pain then improved. Goreisan is dramatically effective for GON as meteorological pain caused by cervical sprain.

A Case Report of Severe Headache after Decompression Craniotomy by Cerebellar Infarction Successfully Treated with a Kampo Formulation Goreisan / 日本東洋医学雑誌

We report a case of severe headache associated with cerebellar infarction was successfully treated with Kampo therapy. The patient complained of severe headache and vertigo in spite of standard therapy after the decompression craniectomy. However, his symptoms were relieved immediately by administration of goreisan. The pharmacological effect of Kampo formulation i.e. goreisan is still unknown, but this formulation has been used for headache with edema, vertigo and vomiting. According to the classic textbook, this formulation has a potential to improve water imbalance in the body, including brain edema. This Kampo medicine is seemed to be an alternative to manage such patients.

Efficacy of Goreisan in Preventing Transurethral Resection Syndrome in Transurethral Resection of the Prostate: A Randomized-Controlled Study.

Objectives: Nonconductive irrigation fluids used during transurethral resection (TUR) of the prostate can cause fluid overload and dilutional hyponatremia. TUR syndrome is generally defined as serum sodium at or below 125 mmol/L with cardiovascular and neurologic symptoms. The aim of this study was to evaluate the effects of Goreisan, a traditional Japanese Kampo medicine, on serum sodium levels and the occurrence of TUR syndrome in patients undergoing TUR of the prostate. Design: This was a randomized-controlled trial. Settings/Location: This trial was conducted at the Osaka Medical College Hospital and Keneikai Sanko Hospital. Subjects: Fifty patients scheduled for TUR of the prostate were included. Interventions: Patients in the Goreisan group (n = 23) received 2.5 g Goreisan orally on the night before surgery and on the morning of surgery. The control group (n = 27) did not receive Goreisan. Surgical procedures, perioperative management, and patient monitoring were otherwise the same in both groups. Outcome Measures: The primary outcome was occurrence of TUR syndrome. The secondary outcome was serum sodium level. Results: Serum sodium remained above 125 mmol/L in all patients, so none of the patients met the criteria for TUR syndrome. However, the Goreisan group had significantly higher intraoperative sodium levels (p < 0.001) and significantly higher intraoperative (p = 0.008) and postoperative (p = 0.02) hemoglobin levels than the control group. Conclusions: These findings indicate that preoperative Goreisan administration can help maintain serum sodium levels in patients undergoing TUR of the prostate.