Evening primrose
Tree primrose; Oenothera biennis of Linnaeus, Grieve’s Cenothera, with Oenothera lamarckiana; in pharmacy Oenotherae oleum, the oil of the seed
- Known today as
- Oenothera biennis, a North American biennial, carried first to Italy and since naturalised on river banks and sandy places across western Europe. The first year makes a flat rosette of leaves; the second, hairy stems three or four feet high with a long succession of large, fragrant, yellow flowers that “usually open between six and seven o’clock in the evening, hence the name of Evening Primrose.” Grieve’s medicine was the bark and leaves; the modern one is the fatty oil pressed or extracted from the seed.
- Kind
- Plant, in 1 older authority
- Constituents
- linoleic acid, gamma-linolenic acid
- Earliest authority here
- Theophrastus, as Grieve reports him (c. 371–c. 287 BC)
- In other databases
- Plants of the World Online · GBIF · Wikidata
Caution. The European agency reports stomach upsets, nausea, soft stools, a rise in temperature, rashes, and headache, and does not recommend the oil for children under twelve, for want of data; overdose causes mild diarrhoea and abdominal pain. The Cochrane review notes a case report warning of possible inflammation, thrombosis, and immunosuppression with use over more than a year, and a study suggesting the oil “may increase bleeding for people on Coumadin” (warfarin).
Evening primrose: what was it used for?
An astringent and sedative in the older practice. The drug, Grieve says, “though not in very general use,” had been employed with success in functional disorders of the stomach and bowels, asthma, and whooping cough, and in dyspepsia, “torpor of the liver,” and certain female complaints such as pelvic fullness. The roots were eaten in some countries in spring, and the French used them to garnish salads. The seed oil, the modern medicine, has been thought beneficial, the Cochrane reviewers note, for its gamma-linolenic acid.
Evening primrose: what does modern science say?
Here the regulator and the trials point different ways. The European Medicines Agency’s herbal committee accepts the oil, taken by mouth, as a traditional herbal medicine “for the symptomatic relief of itching in acute and chronic dry skin conditions exclusively based upon long-standing use” (monograph of 2018). A Cochrane review of 2013, pooling the trials of the oil in eczema, nineteen of them on evening primrose, concluded that oral evening primrose and borage oil “are not effective treatments for eczema,” improvement being similar to placebo. The regulator’s listing is the newer, but it rests on use, not on trials. The oil is 65 to 85 per cent linoleic acid and 7 to 14 per cent gamma-linolenic acid. A 2021 meta-analysis found no effect of the oil on ripening the cervix before labour.
Pharmacognosy & Toxicology
- Constituents
- linoleic acid ChEMBL65 to 85 per cent of the oil
- gamma-linolenic acid ChEMBL7 to 14 per cent
- Mechanism
- Not established in the sources read for this entry.
- Standing
- European Union herbal monograph (2018): traditional use of the oil by mouth, “exclusively based upon long-standing use,” for itching in dry skin conditions. A Cochrane review (2013) found it no better than placebo for eczema.
- European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Oenotherae oleum (Evening primrose oil). EMA/HMPC/753041/2017, 5 June 2018. Read in full · the text read
- European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Oenotherae oleum. EMA/HMPC/753042/2017, 5 June 2018. Read in part · the text read
- Bamford JT, et al. (2013). Oral evening primrose oil and borage oil for eczema. The Cochrane database of systematic reviews. PMID 23633319. Abstract read · the text read
The abstract of each source, beneath its citation. For Club members. About the Club or sign in.
Constituent names open the compound’s record at PubChem, and “ChEMBL” beside a name opens its record at ChEMBL, the European Bioinformatics Institute’s database of bioactive molecules. Where a mechanism line was checked against ChEMBL (ChEMBL 37, read 1 October 2026), the check is shown with the measured value and its source paper, or says plainly that nothing has been measured. Doses are as the references give them, for description only; this is not medical advice. Each source carries the result of its check against Crossref, PubMed, or the authority’s page: see Verification.
Evening primrose: what lore surrounds it?
In the language of flowers, Thiselton-Dyer writes, the evening primrose, from the hour its blossoms open, indicates silent love, refraining from unclosing “her cup of paly gold until her lowly sisters are rocked into a balmy slumber.” Its flowers are fertilised mostly by insects that fly at twilight, Grieve says, though later in the season the plants “keep ‘open house’ practically all day”; in America a troublesome weed, in English gardens one of the showiest hardy plants.
Evening primrose: what did the older authorities say?
- Theophrastus, as Grieve reports him
- The genus name, from Greek oinos, wine, and thera, a hunt, was “an old Greek name given by Theophrastus to some plant, probably an Epilobium, the roots of which were eaten to provoke a relish for wine, as olives are now; others say it dispelled the effects of wine.”
Sources
- Grieve, M. A Modern Herbal, “Primrose, Evening.” As published on botanical.com. Read in full · the text read
- Thiselton-Dyer, T. F. (1889). The Folk-lore of Plants, ch. 14, “Plant Language”. Project Gutenberg, 10118. Read in part · the text read
- European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Oenotherae oleum (Evening primrose oil). EMA/HMPC/753041/2017, 5 June 2018. Read in full · the text read
- European Medicines Agency, Committee on Herbal Medicinal Products. Assessment report on Oenotherae oleum. EMA/HMPC/753042/2017, 5 June 2018. Read in part · the text read
- Bamford JT, et al. (2013). Oral evening primrose oil and borage oil for eczema. The Cochrane database of systematic reviews. PMID 23633319. Abstract read · the text read
- Moradi M, et al. (2021). The effect of evening primrose oil on labor induction and cervical ripening: A systematic review and meta-analysis. Phytotherapy research : PTR. PMID 33913585. Abstract read · the text read
Verification
- Checked
- October 1, 2026
- Passes
- Every sentence read against its sources, in the pass over the remaining 343 entries
- The Standing line checked against the authority it names (EMA, WHO, FDA, CITES, Commission E)
- Every dated or regulatory claim checked by category across the database
- Sources
- 6 cited: 2 read in full, 2 read in part, 2 abstract read. 2 with the abstract on file.
- Corrections
- None were needed.
What was checked, how, and what was found is set out on the Verification page. A checked source is one whose record was found; it does not make the entry medical advice.
Club members can point at a technical term in this entry, such as a constituent, an action, or a word of Jung’s, to read its definition from the source. The Club.
Cite This Entry
Version 1 · first published October 16, 2026
- Chicago
“Evening primrose.” In Materia Medica, edited by B. C. P. Statema. Version 1. The Thinking Press, 2026–. Last modified October 16, 2026. https://thethinkingpress.org/materia-medica/evening-primrose.
- MLA
“Evening primrose.” Materia Medica, edited by B. C. P. Statema, version 1, The Thinking Press, 16 Oct. 2026, thethinkingpress.org/materia-medica/evening-primrose. Accessed 17 Oct. 2026.
- APA
Evening primrose. (2026, October 16). In B. C. P. Statema (Ed.), Materia medica (Version 1). The Thinking Press. Retrieved October 17, 2026, from https://thethinkingpress.org/materia-medica/evening-primrose
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See Also
Sharing linoleic acid, gamma-linolenic acid
Glycine max · Nigella sativa · Sweet almond, oil of · Borago officinalis
Also in Theophrastus
Hemlock in Theophrastus · Cinnabar in Theophrastus · Licorice in Theophrastus · White lead in Theophrastus · everything Theophrastus names →
Drawing on the same sources: Grieve, Thiselton-Dyer
Eyebright · Eucalyptus · Fennel · Endive · Fern seed · the bibliography →
Nearby in the alphabet
The exorcists’ manuals (above all those of the Franciscan Girolamo Menghi) · The eye bead (white, light blue, and black, like an eye) · Eryngo · Ergot · Fairy ring champignon (A small tan mushroom that grows in rings on lawns and pasture) · Epsom salt (the salt of the bitter purging waters near Epsom in Surrey)
Historical description, not medical advice.
