Herb library · Herb · Olea europaea
Olive leaf
The leaf of the olive tree, sold as tea and extract mainly for blood pressure and heart health. Reviews of small trials suggest it may lower blood pressure a little, especially in people with high blood pressure, but EU regulators call the research not rigorous.
Traditional use
An infusion of olive leaves has long been drunk around the Mediterranean and beyond for high blood pressure and to pass more water; the EU assessment records such use in Spain, Madeira, Bulgaria, Brazil and Cuba. In Europe it is registered as a traditional herbal medicine to increase urine flow in mild water retention.
What studies show
- Limited
Blood pressure: a 2022 review of 12 trials (819 people) found a small drop in systolic pressure (about 4 mmHg), larger in people with high blood pressure; one 8-week trial found an extract lowered pressure about as much as a low dose of captopril. The European Medicines Agency says rigorous clinical research is lacking.
- Limited
Cholesterol, triglycerides and blood sugar: results are mixed. The 2022 review found lower triglycerides but no meaningful change in blood sugar; a 2024 review of 12 trials found fasting blood sugar favored the comparison group at low doses and asked for more consistent studies.
- Insufficient
Mild water retention: accepted in the EU on the basis of traditional use only.
Be careful of
Cautions
- ConditionDo not use the tea where you have been told to limit fluids, such as in severe heart or kidney disease. People with heart disease or kidney problems should ask a doctor first. With gallstones there may be a risk of biliary colic.
- NoteIn the largest trial, cough and dizziness were the most common side effects, and a few people had muscle discomfort or headache. Pollen allergy (runny nose or asthma) has been reported.
- NoteUse under 18 has not been established; it is not intended for children. Water retention can have serious causes, so the EU wording requires a doctor to rule them out first.
- PregnancyNot recommended in pregnancy or breastfeeding, because no data are available.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“Oleæ folia. Olive leaves: they are hard to come by here.”
In scripture
Where the Bible names this plant, and which plant scholars think is meant.
The dove came back to him at evening and, behold, in her mouth was a freshly plucked olive leaf. So Noah knew that the waters were abated from the earth.
The olive tree (Olea europaea), whose leaf is on this page. The identification is not disputed (Tristram, 1898). H. B. Tristram, The Natural History of the Bible (1898), p. 373 (opens in a new tab)
Sources
- Oleae folium - herbal medicinal product (opens in a new tab) · EMA · read September 25, 2026
- Assessment report on Olea europaea L., folium (final, 2017) (opens in a new tab) · EMA · read September 25, 2026
- The effects of olive leaf extract on cardiovascular risk factors in the general adult population: a systematic review and meta-analysis (2022) (opens in a new tab) · NIH · read September 25, 2026
- Olive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trials (2024) (opens in a new tab) · NIH · read September 25, 2026
- Olive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril (2011) (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.