If you are considering taking this dietary supplement, it is wise to review existing information on evening primrose oil side effects. Evening primrose oil is a supplement that is extracted from the seeds of the Evening Primrose Plant, properly called Oenothera Biennis. Other common names are Fever Plant, Sun Drop and Oil of Evening Primrose.
This wildflower or herb grows up to eight feet tall and blooms as the sun sets during the summer months. This is why it is called "evening primrose." The next day, the flowers will wither. Seeds that are around five centimeters long are the prize of this herb. From the seeds, an oil is extracted which is rich in gamma linolenic acid (GLA) and omega-6 fatty acids. These substances have given evening primrose oil such a high reputation for pharmaceutical and cosmetic applications.
Most Common Side Effects Associated with Evening Primrose Oil
Below is a table showing reported side effects associated with EPO.
| Side Effect | Description |
| Allergies | While not widely reported, there have nonetheless been incidents of individuals with allergies or adverse reactions to plants in the Onagraceae family having an adverse reaction to EPO. If you are allergic to GLA or any of the other ingredients in evening primrose oil or the gel caps in which the oil is encased, do not take this supplement. A skin rash or other adverse reaction is possible. |
| Seizures | There have been reports of seizures in some people taking evening primrose oil. These reports predominantly included people who had previous seizure disorders, or who were taking evening primrose oil in conjunction with anesthetics. Therefore, people who have seizure disorders should not take evening primrose oil. Use it cautiously if you are taking any prescription drugs, especially those to treat mental illness because of the increased risk of seizure. If you are planning to have surgery for which anesthesia will be required, you should stop taking evening primrose oil at least two weeks before surgery. Ask your surgeon how long you need to be off the oil prior to surgery. Consult with your doctor if you have any adverse effects from taking evening primrose oil. |
| Headache | Some persons have reported headaches associated with the use of evening primrose oil. |
| Lowered Blood Pressure | While studies in animals have shown gamma linolenic acid (GLA) lowers blood pressure, similar studies in humans have not shown consistent changes to blood pressure. Consult with your health professional prior to use if you have low blood pressure. |
| Pregancy and Breastfeeding | To be on the safe side, it is better not to take evening primrose oil if you are pregnant or nursing. There is not enough scientific evidence to show what effects, if any, that EPO has on pregnant women, fetuses or nursing infants. |
| Gastrointestinal Upset | Some people have reported gastrointestinal upset, but it is not common. Most people tolerate evening primrose oil. Consult your health care professional if you experience any side effects you believe are associated with evening primrose oil usage. |
Additional Precautions
Since the U.S. Food and Drug Administration does not regulate supplements or herbs, there is no guarantee of safety of products, strength or purity. Always read the label of dietary supplements and do due diligence regarding the manufacturer's reputation. Consult a health care professional prior to using dietary supplements to treat an illness.
