Does Olive Leaf Extract Upset The Stomach?

Though olive leaf extract is not a well-studied remedy, it's purported to treat diabetes, high blood pressure, infections and inflammation. It also is being studied as a nutraceutical in the prevention of human cancer. The leaf's major component, oleuropein, has antioxidant properties. Olive leaf also has antibacterial and antifungal properties. Olive leaf's side effects, such as stomach upset, are not well documented as of 2011. Always consult a health care professional before using an herbal remedy.

Side Effect Documentation

If you drink olive leaf tea on an empty stomach, you may experience stomach upset, notes the ethnobotany website Sacred Earth. Stomach upset is not documented in scientific literature as an olive leaf extract side effect, however. The lack of side effects documented may be due to the fact that the supplement is not well-studied, note the experts at Drugs.com.

Allergic Reaction

It's possible to suffer an allergic reaction to olive leaf. One potential symptom of an allergic reaction is nausea. Other symptoms may include vomiting, abdominal pain or cramps, diarrhea, itching, hives, watery eyes, nasal congestion, a rash, trouble breathing or swallowing, chest tightness, anxiety, and light-headedness. If you experience an allergic reaction, seek immediate medical attention.

Hypoglycemia

Olive leaf does raise your risk for hypoglycemia, or blood-glucose levels that fall too low, especially if it's taken along with medicines to control diabetes. It also can raise risk for hypoglycemia when taken with other herbs that have blood-sugar lowering properties such as garlic, bitter melon, fenugreek, ginseng and bilberry. Hypoglycemia can cause a general feeling of malaise, or illness. More common symptoms of hypoglycemia include hunger, headaches, a fast heartbeat, nervousness, trouble sleeping, nervousness or aggression, unclear thinking, tiredness or weakness, cold sweats, and trembling.

Herxheimer Reaction

Olive leaf manufacturers caution users that their product can lead to a Herxheimer reaction, which can cause gastrointestinal upset as well as headaches and other flu-like symptoms. Advocates of detoxification call this a "die-off" reaction caused by toxins related to dead microbes in your body being released faster than your body can process them, according to "The Complete Idiot's Guide to Detoxing Your Body," by Delia Quigley.