Pumpkin seed oil (Cucurbita pepo) versus tamsulosin for benign prostatic hyperplasia symptom relief: a single-blind randomized clinical trial. BACKGROUND: Benign prostatic hyperplasia (BPH) is very common in aging men. We aimed to compare the effects of tamsulosin and pumpkin (Cucurbita pepo) seed oil on BPH symptoms. METHODS: This single-blind randomized clinical trial included patients with BPH aged ≥ 50 years referred to the Urology Clinic of Shahid Beheshti Hospital, Hamadan, Iran, from August 23, 2019 to February 19, 2020. Patients were randomized into two groups. One group received 0.4 mg tamsulosin every night at bedtime and the other received 360 mg pumpkin seed oil twice a day. Patients' age, weight, height, and body mass index (BMI) were recorded. The International Prostate Symptom Score (IPSS) was filled out by the patients at baseline and then 1 month and 3 months after the initiation of treatment. The BPH-associated quality of life (QoL), serum prostate-specific antigen, prostate and postvoid residual volume, and maximum urine flow were also assessed at baseline and 3 months later. Drug side effects were also noted. RESULTS: Of the 73 patients included in this study with a mean age of 63.59 ± 7.04 years, 34 were in the tamsulosin group and 39 in the pupkin seed oil group. Patients were comparable with respect to age, weight, height, BMI, and baseline principal variables in both groups. Also, there was no significant difference between groups in terms of principal variables at any time point. However, there was a significant decrease in IPSS and a significant improvement in QoL in both groups. Although the decrease in IPSS from baseline to 1 month and 3 months was significantly higher in the tamsulosin group compared to the pumpkin group (P = 0.048 and P = 0.020, respectively), the decrease in IPSS from 1 to 3 months was similar (P = 0.728). None of the patients in the pumpkin group experienced drug side effects, while dizziness (5.9%), headache (2.9%), retrograde ejaculation (2.9%), and erythema with pruritus occurred in the tamsulosin group. CONCLUSIONS: Pumpkin (Cucurbita pepo) seed oil relieved BPH symptoms with no side effects, but was not as effective as tamsulosin. Further studies are required to confirm the role of pumpkin seed oil as an option for the treatment of BPH symptoms. Trial registration Iranian Registry of Clinical Trials, IRCT20120215009014N340. Registered 19.02.2020. Retrospectively registered, https://en.irct.ir/trial/45335 .