Evening Primrose

About 125 species of annuals, biennials, nd perennials, belong to this N American genus, many of which are widely naturalized in other parts of the world. They are related to willow herbs (Epilobium species), but not to primroses (Primula species , See, Primrose). Oenothera biennis is a tall plant with scented flowers that thrives in very poor soil; it naturalizes well in sandy coastal gardens, steep banks, and gravel. According to Mrs. Grieve (A Modern Herbal, 1931), a drug was made from the leaves and stem peelings of O. biennis to treat asthma, gastrointestinal disorders, whooping cough, and "certain female complaints, such as pelvic fullness". The medicinal uses of evening primrose oil are a recent discovery, following scientific research in the 1980s that demonstrated its effectiveness for a wide range of intractable complaints. The oil contains gammalinolenic acid (GLA), and unsaturated fatty acid that functions as a precursor in the production of hormone-like substances. Through deficiencies in the diet or digestion, this fatty acid may be absent or blocked, causing disorders that affect uterine muscles, blood vessels, nervous system, and metabolism. Evening primrose oil is also produced from O. gazioviana and O. parviflora, GLA is also found in the seeds of Borago officinalis (See, Borage) and Ribes nigrum (See, Black Currant). A drug produced from GLA has shown promising results in the treatment of various cancers, notably pancreatic cancer. Oenothera may derive from the Greek oinos, "wine", and thera, "hunt", from a name given by Theophrastus to a plant whose roots were eaten to arouse desire for wine.

Used for medicinal purposes for centuries, the oil taken from the seed of the evening primrose contains gamma-linolenic acid (GLA), and essential fatty acid thought to be in short supply in many people's diets. Evening primrose oil has been used to treat breast tenderness associated with premenstrual syndrome, arthritis, eczema, allergies, hyperactivity in children, dry eyes, and numbness and tingling in the hands and feet.

Erect annual or biennial with a rosette of oblanceolate basal leaves, 20cm (8in) long. Yellow, bowl-shaped flowers, to 5cm (2in) across, open in the evening throughout summer and autumn, followed by downy pods containing tiny seeds.

Common Name:
Evening Primrose
Other Names:
Evening Star, Fever Plant, Field Primrose, King's Cureall, Night Willow Herb, Sun Drop, Tree Primrose.
Botanical Name:
Oenothera biennis
Native Location:
Eastern N America, widely naturalized
Well-drained to dry soil, including sandy and stony soils, in sun. Plants may succumb to root rot in wet conditions. Powdery mildew may attack leaves. Self-sows freely in optimum conditions.
By seed sown in autumn
Leaves, stem bark, flowers and immature pods are collected in summer and used fresh. Seeds are collected when ripe and pressed for oil, which is combined with vitamin E to prevent oxidation.
1-1.5m (3-5ft)
22-30cm (9-12in)
The fragrant, yellow-flowered, night-blooming evening primrose is native to North America (though now found throughout Europe). The whole plant was a staple food of the Native American Blackfoot tribe and was used extensively by other Native Americans to treat colds, "female" complaints, stomach ailments, and whooping cough. Early American settlers soon learned about the plant's therapeutic values, and by the early nineteenth century it was a prized medicine among the Shakers. They called it "scabbish", and used it to treat colds and coughs. Its unusual botanical name, Oenothera, means "a wine hunt", from the Greek oinos (for "wine") and thera (for "a hunt"). Scholars believe the name was coined by Theophrastus, a third-century B.C.E. Greek philosopher and naturalist—and Theophrastus was actually describing another plant entirely. Many researchers think that plant was the wickup (Epilobium angustifolium), an ancient hangover remedy and, ironically, another famed Shaker herb, used to treat diarrhea and dysentery.
Parts Used:
Leaves, stem bark, flowers, pods, oil taken from the seed, Whole Plant.
An astringent, soothing herb. Oil is alterative, regulating hormonal systems.
Medicinal Uses:
Internally for whooping cough, asthma, and digestive problems (leaves, stem bark, flowers). Externally for rheumatic pain (Leaves, stem bark, flowers). Internally for premenstrual and menopausal syndromes, circulatory problems (such as intermittent claudication), eczema, acne, brittle nails, hyperactivity in children, rheumatoid arthritis, coronary artery disease, complications of diabetes, alcohol-related liver damage, and multiple sclerosis (oil). Contraindicated in schizophrenia, and with phenothiazine drugs in the management of epilepsy. Excess may have laxative effects and cause abdominal pain. Externally for dry skin, scaly and itchy skin disorders, and brittle nails. (oil).
To treat elevated cholesterol levels, premenstrual syndrome, perimenopausal hot flashes, elevated blood pressure, rheumatoid arthritis, and multiple sclerosis.
Evening primrose has antispasmodic, astringent, demulcent, and sedating properties. It is sometimes taken internally for colds and coughs and is applied externally to heal wounds and soothe a variety of skin ailments. But it is most frequently prescribed for the symptoms of premenstrual syndrome (PMS) and menopause, including abnormal bloating, breast pain, anxiety, cramps, hormonal imbalances, restlessness, and sleep disturbances. Evening primrose oil, which is extracted from the plant's seeds, has been the subject of intense clinical study over the last 20 years. Research confirms that evening primrose, like borage, contains the essential fatty acid GLA (gamma-linoleic acid). Besides helping to prevent atherosclerosis (hardening of the arteries), GLA is converted in the body to hormonelike substances called prostaglandins that regulate many organ functions as well as reduce pain and swelling. Evening primrose oil may also be a powerful anticlotting agent and therefore useful in helping to prevent heart attacks.
Evening primrose and evening primrose oil are widely available, alone or in combination with other herbs, in teas and capsules. Follow the manufacturer's directions. To make a tea, Pour 1 cup of boiling water over 1 teaspoon of dried herbs and steep for 5 minutes. Drink up to 1 cup a day, 2 teaspoons at a time.
Typical Dose:
A typical daily dose of evening primrose oil may range from 540 mg to 6 gm.
Do not take evening primrose if you are pregnant or trying to conceive. If you have a blood-clotting disorder, talk with your medical practitioner before using the herb.
Possible Side Effects:
Evening Primrose oil's side effects include bloating, nausea, vomiting, diarrhea, and flatulence. It may also increase the risk of pregnancy complications.
Drug Interactions:
Taking evening primrose oil with these drugs may increase the risk of bleeding or bruising:
Abciximab, (ReoPro)
Alteplase, (Activase, Cathflo Activase)
Antithrombin III, (Thrombate III)
Argatroban, (Argatroban)
Aspirin, (Bufferin, Ecotrin)
Aspirin and Dipyridamole, (Aggrenox)
Bivalirudin, (Angiomax)
Clopidogrel, (Plavix)
Dalteparin, (Fragmin)
Danaparoid, (Orgaran)
Dipyridamole, (Novo-Dipiradol, Persantine)
Drotrecogin Alfa, (Xigris)
Enoxaparin, (Lovenox)
Eptifibatide, (Integrillin)
Fondaparinux, (Arixtra)
Heparin, (Hepalean, Hep-Lock)
Hydrocodone and Aspirin, (Damason-P)
Hydrocodone and Ibuprofen, (Vicoprofen)
Ibritumomab, (Zevalin)
Indobufen, (Ibustrin)
Lepirudin, (Refludan)
Nadroparin, (Fraxiparine)
Reteplase, (Retavase)
Streptikonase, (Streptase)
Tenecteplase, (TNKase)
Ticlopidine, (Alti-Ticlopidine, Ticlid)
Tinzaparin, (Innohep)
Tirofiban, (Aggrastat)
Urokinase, (Abbokinase)
Warfarin, (Coumadin, Jantoven)
Taking evening primrose oil with these drugs may lower the seizure threshold:
Acetazolamide, (Apo-Acetazolamide, Diamox Sequels)
Amobarbital, (Amytal)
Barbexaclone, (Maliasin)
Carbamazepine, (Carbatrol, Tegretol)
Chlorpromazine, (Largactril, Thorazine)
Clonazepam, (Klonopin, Rivotril)
Clorazepate, (Tranxene, T-Tab)
Diazepam, (Apo-Diazepam, Valium)
Ethosuximide, (Zarontin)
Felbamate, (Felbatol)
Fluphenazine, (Modecate, Prolixin)
Fosphenytoin, (Cerebyx)
Gabapentin, (Neurontin, Nu-Gabapentin)
Lamotrigine, (Lamictal)
Levetiracetam, (Keppra)
Lorazepam, (Activan, Nu-Loraz)
Mephobarbital, (Mebaral)
Mesoridazine, (Serentil)
Methsuxemide, (Celontin)
Metronidazole, (Flagyl, Noritate)
Moxifloxacin, (Avelox, Vigamox)
Nortriptyline, (Aventyl HCl, Pamelor)
Ofloxacin, (Floxin, Ocuflox)
Olanzapine, (Zydis, Zyprexa)
Oxazepam, (Novoxampam, Serax)
Oxcarbazepine, (Trileptal)
Pentobarbital, (Nembutal)
Perphenazine, (Apo-Perphenazine, Trilafon)
Phenobarbital, (Luminal Sodium, PMS-Phenobarbital)
Phenytoin, (Dilantin, Phenytek)
Primidone, (Apo-Primidone, Mysoline)
Prochlorperazine, (Compazine, Compro)
Promethazine, (Phenergan)
Quetiapine, (Seroquel)
Thiethylperazine, (Torecan)
Thiopental, (Pentothal)
Thioridazine, (Mellaril)
Thiothixene, (Navane)
Tiagabine, (Gabitril)
Topiramate, (Topamax)
Tramadol, (Ultram)
Trifluoperazine, (Novo-Trifluzine, Stelazine)
Valproic Acid, (Depacon, Depakote ER)
Venlafaxine, (Effexor)
Vigabatrin, (Sabril)
Zonisamide, (Zonegran)
Lab Test Alterations:
  • May increase bleeding time, due to gamma-linolenic acid (GLA) content.
  • May lower plasma triglycerides and increase HDL "good" cholesterol due to GLA content.
Supplement Interactions:
Increased risk of bleeding when used with herbs and supplements that might affect platelet aggregation, such as Angelica, Danshen, Garlic, Ginger, Ginkgo Biloba, Red Clover, Turmeric, White Willow, and others.
Culinary Uses:
Young leaves are added to salad or cooked as a potherb. Flowers are edible. Parsnip-like roots are cooked as vegetables or added to soups or stews. Immature pods are steamed or stir-fried.
Economic Uses:
Oil is added to food supplements, skin products, and cosmetics.
Encyclopedia of Herbs by Deni Brown Copyright © 1995, 2001 Dorling Kindersley Limited Pp 293-294
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.212-214
The Modern Herbal Primer by Nancy Burke Copyright©2000 Yankee Publishing, Inc. pp. 29-30