BACKGROUND AND OBJECTIVE: Menopause is a global phenomenon for women and about 74 to 80% of women worldwide suffer from symptoms of menopause. The symptoms women experience during this period include night sweats, sleep disorders, heart problems and flushing. The treatment currently used for these complications is hormone replacement method, which has serious side effects. One alternative method for the hormone replacement method is the use of plants from the family of phytoestrogens such as evening primrose. METHODS: This triple-blind clinical trial was conducted among 100 postmenopausal women with menopausal symptoms in both drug and placebo groups. First, the symptoms of menopause were measured based on scores of 0 – 16. The participants arbitrarily used placebo or evening primrose oil 1g perle twice a day for one month. After one month, the symptoms of menopause were measured and compared using Menopause Health Questionnaire. IRCT:1N2017012432161. FINDINGS: The results of the study demonstrated that evening primrose has considerable effects on the reduction of flushing (3.33±0.79 vs. 0.89±0.64), sleep disorders (2.65±0.6 vs. 1.3±0.66) and musculo-skeletal disorders (3.41±0.74 vs. 3.41±0.73 vs. 0.82±0.73) in evening primrose group compared with placebo group (p