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Herb library · Herb · Oenothera biennis

Evening primrose oil

An oil pressed from the seeds of a yellow wildflower that opens at sunset, rich in the omega-6 fat GLA and sold for eczema, PMS, breast pain and menopause. There's not enough evidence that it helps any health condition, and studies found it no better than placebo for eczema or breast pain.

Traditional use

Evening primrose is native to North and South America and grows in Europe and parts of Asia. Native Americans put juice from the stem and leaves on the skin for inflammation, bruises and minor wounds, and used the leaves by mouth for stomach complaints and sore throat. Today the seed oil is sold for eczema, rheumatoid arthritis, PMS, breast pain and menopause symptoms, and has been used to try to start labor.

What studies show

  • Limited

    Eczema (atopic dermatitis): a substantial number of studies; taken by mouth, it has not been shown to relieve symptoms.

  • Limited

    Breast pain: it is probably no more effective than a placebo.

  • Limited

    Starting labor at the end of pregnancy: studies, oral or vaginal, have had inconsistent results.

  • Insufficient

    Rheumatoid arthritis, PMS and menopause symptoms: there's insufficient evidence to show whether it helps.

Be careful of

Cautions

  • NoteProbably safe for most adults by mouth and generally well tolerated; the most common side effects are abdominal pain, nausea and diarrhea. Less is known about children.
  • PregnancyIt may be safe in pregnancy and breastfeeding, but the evidence is not conclusive. The long-term safety of using it to start labor has not been established. In breastfeeding it raises GLA in breast milk, with no harm to infants reported.
  • InteractionSome herbs and medicines interact in harmful ways; ask before combining it with any medicine.
  • Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.

Sources

  1. Evening Primrose Oil: Usefulness and Safety (opens in a new tab) · NCCIH · read September 25, 2026

Reviewed September 25, 2026.