Evening primrose oil

Evening primrose (Oenothera biennis) is a tall, hardy, native biennial of the Onagraceae family. Its Latin name is derived from the Greek word oinos for wine and thera for hunt and reflects the folk belief that the herb could minimize the ill effect of over-indulgence in wine following a hunt.

The plant thrives in dry, sunny meadows, and is abundant in many parts of the world. The leaves of the firstyear plant form a bright-green, basal rosette. In the second year, the coarse, erect stalk reaches up to 4 ft (1.2 m) with hairy, alternate, lanceolate leaves with a distinctive mid rib. Leaves grow from 3–6 in (7.6–15.2 cm) long.

The blossoms are pale yellow with a slight lemon scent and a cup-like shape. They grow in clusters along the flower stalk, and bloom from June to September, opening at dusk to attract pollinating insects and night-flying moths. These phosphorescent blossoms inspired a common name for the herb: evening star. The seeds grow within an oblong, hairy capsule. The root is large and fleshy.

General use

The medicinal components of evening primrose are found in the seed-extracted oil, which contains essential fatty acids including gamma linoleic acid (GLA). GLA is often deficient in the Western diet and is needed to encourage the production of prostraglandins. Low levels of essential fatty acids may increase the symptoms of premenstrual syndrome (PMS), diabetes, etc. Evening primrose oil has been used to treat PMS and menopausal symptoms, asthma, and has been shown to reduce high blood cholesterol levels.

Research conducted in Great Britain has indicated that evening primrose oil can also be medicinally useful in the treatment of nerve disorders, such as multiple sclerosis and rheumatoid arthritis.

The essential oil does appear to be of some benefit in cases of alcohol poisoning and in alleviating hangovers, and to ease symptoms of alcohol withdrawal. The oil can also help relieve dry eyes, brittle nails, and acne when combined with zinc. When taken as a supplement, evening primrose has helped to promote weight loss.

Traditionally, Native Americans valued evening primrose as a treatment for bruises and cuts. The Flambeau Ojibwe tribe soaked the whole plant in warm water to make a poultice for healing bruises and to overcome skin problems.

Oenothera biennis

The mucilaginous juice in the stem and leaf can be applied externally to soothe skin irritations, or may be eaten to relieve digestive discomfort and for its stimulating effect on the liver and spleen. The astringent properties of the plant are helpful to soothe inflamed tissue. The plant has sedative properties and has been used to decrease hyperactivity in children.

The entire plant is edible. The root from the firstyear growth is a nutritious pot herb. Boiled roots taste somewhat like parsnips.

Evening primrose oil is valued for its antioxidant properties. Antioxidants are substances that counteract the damaging effects of oxidation in living tissue. A team of Canadian researchers has recently identified the specific antioxidant compounds in evening primrose oil; one of them, a yellow substance known as catechin, appears to inhibit the growth of cancerous tumors and to lower the risk of heart disease.


Evening primrose oil is prepared commercially and widely available in health food stores. The extract should be stored in a cool, dry place in order to avoid spoilage. Capsules are also available. Correct dosage should be decided in consultation with a practitioner.

An ointment can be prepared by mixing one part of the diced plant with four parts of heated petroleum jelly. Stored in a tightly closed container and refrigerated, the consistent preparation will maintain its effectiveness. Apply as needed to soothe the skin.


Use by persons with epilepsy is discouraged because evening primrose oil appears to lower the effectiveness of medications used to treat epilepsy. Physicians should be consulted before using evening primrose oil on children.

Side effects

There have been some reports of headache, nausea, loose stools, and skin rash after using evening primrose preparations.