Background By 2025, the number of postmenopausal women is expected to approach 1.1 billion worldwide. Menopausal symptoms can be severe that it affects quality of life (QOL) of menopausal women. So, the aim of this study was to assess the effect of folic acid on the frequency, severity, score of hot flashes and QOL of post-menopausal women. Methods A double blinded randomized placebo-controlled clinical trial was conducted at El Mahsama Family Practice Center, Ismailia, Egypt, carried out between August 2019 and October 2020 on 100 postmenopausal women who were randomly allocated into two groups: 5mg /daily folic acid group or identical-appearing placebo group for 4 weeks. A semi-structured questionnaire was used to collect data on socio-demographic characteristics and obstetric history. Daily hot flashes record was used to gather information about the frequency, severity, score of hot flashes. QOL was assessed by menopause specific quality of life (MENQOL). Results There was statistically significance difference between both groups regarding hot flashes frequency, severity and hot flashes score (p < 0.015, 0.001, and 0.002) respectively. Folic acid group shows that 22% of participants were clinically improved compared with no clinical improvement among the placebo group (χ2 = 12.360, p < 0.001). It was found that there was no statistically significant difference between intervention and control group regarding their MENQOL domains after treatment. Conclusion Folic acid was effective in reducing frequency, severity, and hot flashes score in postmenopausal women so it can be recommended as an accessible and affordable method to treat hot flashes.