Olive Leaf (Olea europaea): Uses, Evidence and Safety

Safety first. Olive leaf products have been studied for lowering blood pressure, so anyone who takes blood pressure or diabetes medicine should tell the prescriber or pharmacist before adding one. The EU herbal committee says olive leaf medicines must not be used by people who are told to limit fluids, such as those with severe heart or kidney disease. [1] It also says safety in pregnancy and breastfeeding has not been established and that use under 18 has not been established. [2] See How Interactions Work.

Overview

Olive leaf is the leaf of the olive tree, not the fruit or the oil. [1] It is sold as dried leaf for tea, as capsules and as concentrated extracts. This page covers the leaf. For olive oil as a food, see Olive Oil. The trials below mostly tested extracts, and a result for one extract does not carry over to a cup of leaf tea.

Scientific name and plant part

• Accepted name: Olea europaea L., family Oleaceae, according to the GBIF plant database. [3]
• Part used: the leaf. The EU committee's conclusions cover fresh or dried leaves and preparations made by drying and powdering them. [1]

Traditional use (not proof)

A 2012 trial paper notes that olive leaves have been widely used in traditional remedies in European and Mediterranean countries, as extracts, herbal teas and powder. [4] The EU herbal committee (HMPC) accepted, on the basis of long-standing use, that olive leaf can be used to promote water elimination through the kidneys in mild water retention, in adults, after a doctor has ruled out serious conditions. [1] It said this rests on long-standing use because clinical evidence was insufficient. [1] Tradition is respected as history here and is not treated as proof.

What research shows (research, not tradition)

Beyond these uses, Proper evidence not found in the sources we read. We searched PubMed for olive leaf extract with blood pressure, blood sugar and adverse effects, and read the EU regulator's summary and monograph.

Forms and why the form matters

Trials used extracts with different contents. One crossover trial gave 136 mg oleuropein a day. [9] Another gave 51.1 mg oleuropein a day. [12] Because of this, the results of one product cannot be assumed for another. The EU committee's conclusions cover leaf teas and solid forms and exclude combination products. [1] See Standardized Herbal Extracts Explained.

Safety and who should ask first

• Medicines: the EU monograph (2017) lists no interactions as reported. [2] Our reading, not a documented harm: the trials above show blood pressure effects close to a prescription medicine, so a prescriber should know about the combination. See Herbs and Diabetes, Blood Pressure and Heart Medicines.
• Heart and kidney conditions: the monograph says people with cardiac disease or renal impairment should seek medical advice first. [2]
• Pregnancy and breastfeeding: not established; the monograph does not recommend use. [2] See Pregnancy and Breastfeeding.
• Children: not established under 18. [2]
• Side effects: the 621-person trial reported no significant adverse events. [6] The EU monograph lists none known. [2]
• Liver and kidney blood tests: a 2022 review found no meaningful change, but rated this evidence low to very low quality. [7]
• Allergy, bleeding and surgery: the sources we read did not give olive-leaf-specific points. Tell the surgical team about every herb you use. See Supplements Before Surgery.
• Quality: contents of products can differ from labels. See Quality Testing and Certifications.

Official statements

• EU herbal committee (HMPC), monograph dated 31 January 2017: traditional use for mild water retention in adults; contraindicated where fluid intake must be limited. [2][1]