Evening Primrose Oil: Eczema, PMS, Menopause and Pregnancy Evidence and Cautions
What reviews and trials found for evening primrose oil in eczema, PMS, menopause and late pregnancy, plus side effects, bleeding, seizure and pregnancy cautions.
Content last updated . This page has not been medically reviewed.
Quick answer
Evening primrose oil (EPO) is promoted for eczema, PMS, breast pain, menopause symptoms and starting labor. NCCIH says there is not enough evidence to support it for any health condition. [1] This page looks at each use separately, because a result in one group (for example, a vaginal capsule at term pregnancy) says nothing about another (a daily capsule for PMS). It is information only, not advice. For the oil itself and GLA, see Evening primrose oil, borage oil and GLA.
How to read the evidence labels
Labels used below: no benefit shown (good studies found no difference from placebo), mixed, insufficient evidence, promising but limited. A change in cervix softness score or a symptom score is not the same as a healthier birth or a better life, so we say which outcome was measured.Eczema
A Cochrane review of 27 studies with 1,596 people found oral EPO did not significantly improve global eczema symptoms compared with placebo, and concluded that oral borage oil and EPO are not effective treatments for eczema. [2] NCCIH likewise says oral EPO has not been shown to help atopic dermatitis. [1] Label: no benefit shown. See Eczema for care options and when to see a doctor.PMS and breast pain
Two systematic reviews of herbs, vitamins and minerals for premenstrual syndrome found no benefit of EPO over placebo. [3] [4] NCCIH says EPO is probably not more effective than placebo for breast pain. [1] Label: no benefit shown. For other PMS options see PMS and PMDD. Severe mood symptoms or thoughts of self-harm need prompt help from a clinician; in the US, call or text 988.Menopause hot flashes and night sweats
A 2024 meta-analysis of trials found hot-flash severity was lower with EPO than placebo when used under 6 months, but no difference in frequency or duration, and concluded the evidence was insufficient for firm conclusions. [5] One single-blind trial in postmenopausal women (8 weeks) reported fewer and milder night sweats with EPO but no clear change in hot flashes. [6] Label: mixed, insufficient evidence. See Perimenopause and menopause and hormone-balance claims.Frequently asked questions
Does evening primrose oil help PMS?
Two systematic reviews found no benefit over placebo. [3] [4]
Does evening primrose oil help menopause hot flashes?
A 2024 meta-analysis found insufficient evidence, with lower severity but no change in frequency or duration. [5]
Can evening primrose oil start labor?
Results are inconsistent: a 2023 meta-analysis and a vaginal-capsule trial were favorable on cervical measures, while an oral-capsule trial found no difference in labor outcomes. [7] [8] [9] Ask your midwife or doctor.
Is it safe in pregnancy?
NCCIH says it may be safe but the evidence is not conclusive. [1] A pregnancy review reported severe adverse events. [11]
Can I take it with a blood thinner or before surgery?
Ask a pharmacist or prescriber. The Cochrane review mentions possible extra bleeding with warfarin. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Late pregnancy and starting labor
This is where results are least consistent, and route and design matter.
| Study type | What was found | Label |
|---|---|---|
| Meta-analysis of 9 trials, EPO for cervical ripening at term | Higher cervical ripening score, fewer cesarean births and shorter first stage of labor; the authors note differences between studies [7] | Promising but limited |
| One vaginal 1,000 mg capsule trial, 48 women per group, vs placebo | Higher cervical score and less need for induction with EPO [8] | Promising but limited |
| Oral EPO trial, 80 low-risk first-time mothers at 40 weeks, vs placebo | No significant difference in gestational age at delivery, need for induction or labor length [9] | No benefit shown |
| Oral EPO from week 37, 54 vs 54 women, retrospective birth-center study | Associated with more prolonged rupture of membranes and other interventions; not a randomized trial [10] | Possible harm signal, low certainty |
NCCIH says studies of oral or vaginal EPO for starting labor have had inconsistent results and long-term safety is not established. [1] A 2014 review of herbal therapies in pregnancy found very few scientific data to support such use and reported severe adverse events with EPO. [11] The trials above are study amounts, never advice. Do not use EPO to try to start labor without your midwife or obstetrician; see Pregnancy and breastfeeding and Prenatal and postnatal vitamins.
Side effects and cautions
- Common effects. NCCIH lists abdominal pain, nausea or diarrhea; the 2024 menopause review mentions mild nausea and headache. [1] [5]
- Bleeding and blood thinners. The Cochrane authors cite a study suggesting EPO may increase bleeding in people on warfarin. [2] Ask a pharmacist; see Medication interactions. Tell your surgical team about it before procedures: Supplements before surgery.
- Seizures. A concern that EPO might lower the seizure threshold dates from two early-1980s reports. A 2007 review argues the link is spurious and that medicine references should drop it. [12] That is one author's argument, not a regulator's position. If you have epilepsy or take seizure medicines, ask your neurologist or pharmacist first.
- Long-term use. A case report mentioned in the Cochrane review warns about use beyond one year; the trials were short. [2]
- Breastfeeding. NCCIH says EPO raises GLA in breast milk without a link to harm in the infant, but evidence is not conclusive. [1]
- Children, kidney and liver conditions. Less is known in children. [1] For kidney and liver conditions: proper evidence not found in the sources we read.
- Quality. See Quality testing and certifications.
References
- NCCIH, Evening Primrose Oil. Read 2026-10-22.
- Bamford JT et al. Oral evening primrose oil and borage oil for eczema. Cochrane systematic review, 2013. Read 2026-10-22.
- Herbs, vitamins and minerals in the treatment of premenstrual syndrome: a systematic review. 2009. Read 2026-10-22.
- Herbal treatments for alleviating premenstrual symptoms: a systematic review. 2011. Read 2026-10-22.
- Evening primrose oil for menopause hot flashes: systematic review and meta-analysis. 2024. Read 2026-10-22.
- The effect of evening primrose oil capsule on hot flashes and night sweats in postmenopausal women: a single-blind randomized controlled trial. 2021. Read 2026-10-22.
- Evening primrose oil for cervical ripening in term pregnancies: a systematic review and meta-analysis. 2023. Read 2026-10-22.
- The use of evening primrose oil for cervical ripening in low-risk women with term pregnancy: a randomized double-blinded controlled trial. 2024. Read 2026-10-22.
- Evening primrose oil and labour, is it effective? A randomised clinical trial. 2018. Read 2026-10-22.
- Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women. 1999. Read 2026-10-22.
- Herbal therapies in pregnancy: what works? 2014. Read 2026-10-22.
- The safety of evening primrose oil in epilepsy. 2007. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.