Borage (Borago officinalis): Uses, Evidence and Safety

Safety first: liver, pregnancy, and a toxic look-alike

Borage leaf, flower and tea contain small amounts of pyrrolizidine alkaloids (PAs), plant compounds that can damage the liver. Memorial Sloan Kettering (MSK) names the PAs in borage (including amabiline) and says the risk of liver damage rises with length of exposure and total amount taken. [1] The EU herbal committee (HMPC, 2014) says liver toxicity from the toxic, unsaturated PAs is established, and lists borage among leafy PA plants that are recommended as salads. [2] MSK advises that borage oil should not be used in pregnancy or breastfeeding, or by people with liver disease, and should only be used if certified free of unsaturated PAs. [1] Young borage plants can also be confused with foxglove (Digitalis), which is poisonous to the heart; poisonings from this mix-up are in the medical literature. [7][8] Borage is also very high in nitrates, which have been linked to a blood disorder in infants. [9] For a swallowed plant or product, Poison Help is 1-800-222-1222 in the US; for collapse or severe symptoms call 911. See the full PA page: pyrrolizidine alkaloids in comfrey, coltsfoot and borage.

Overview

Borage is Borago officinalis L., a plant in the family Boraginaceae; GBIF lists it as the accepted name. [3] Its native range was not found in the sources we read. In this page "borage" means three different things that should not be mixed up: (1) the fresh or dried leaf and flower, eaten as a salad or garnish or brewed as a tea; (2) the seed oil sold in capsules as a source of gamma-linolenic acid (GLA), an omega-6 fat; and (3) extracts. [1][10] MSK describes borage oil as roughly a quarter GLA, compared with about a tenth for evening primrose oil. [1] The oil is covered in more detail on evening primrose, borage and GLA oils and, for the sister oil, evening primrose.

Traditional use (not proof of benefit)

MSK says borage oil has been used in herbal and traditional medicine to induce sweating, as an expectorant (to loosen phlegm), as an anti-inflammatory, to promote breast-milk production, to stimulate the adrenal glands, and as an alternative source of GLA to evening primrose oil. [1] The plant's mucilage (sticky plant sugars) is thought to act as an expectorant. [1] These are traditional uses, not results of trials. Borage leaves have also been a food: the EU committee notes them as salad leaves and as an ingredient in a traditional German green sauce. [2]

What research shows

Almost all human research is on the seed oil, not on the leaf, flower or tea. [1]

Borage leaf or tea for any health purpose: Proper evidence not found in the sources we read.

Forms and why the form matters

• Fresh leaf and flower (salad, garnish): a food use with a documented PA hazard and, in some cases, very high nitrate content. [2][9]
• Tea or herbal infusion: a 2023 laboratory paper says PAs from borage consumed as herb and tea may pose a food-safety risk, and that the EU set maximum PA levels for borage, among other foods, which apply from 1 July 2022. [10] The same paper found that acetylated PAs, which the EU rules do not regulate, were among the most important in borage leaves. [10]
• Seed oil in capsules: the seed is the source of GLA. MSK says borage oil contains small amounts of PAs unless it is certified free of them, and cites a certification criterion of no more than 0.5 to 1 microgram of PAs per gram of oil and a German agency recommendation of no more than 1 microgram of PAs a day. [1] These are official figures, not advice to take any amount. We could not confirm from the sources we read how many products on sale meet that standard.
• Extracts: the one asthma trial used an extract; product content is not described. [1]

Safety in more detail

• Liver: MSK lists liver disease as a reason not to use borage oil, and also advises against it with liver-toxic medicines such as anabolic steroids and ketoconazole, because of the small PA amounts. [1] PA liver injury can be slow to show: the EU committee says symptoms may take days or months to appear. [2] See herbs and liver injury and liver warning signs.
• Common side effects: headache, abdominal pain, nausea, belching and loose stools. [1] In the eczema trials, side effects were mostly mild stomach complaints, and the reviewers noted these short trials say nothing about long-term use. [4]
• Seizures: MSK reports one case of continuous seizure activity in a healthy 41-year-old woman after one week of borage oil. [1] This is a single case report. See epilepsy and seizure risk with herbs and oils.
• Medicines: MSK lists blood thinners such as warfarin (possible increased bleeding, reasoned from a study of evening primrose GLA, not borage itself), and says NSAIDs could in theory reduce borage oil's effect. [1]
• Pregnancy: MSK says borage oil may cause birth defects and premature labor, and that it should not be used. [1] The EU committee, discussing high-PA products in general, cites a report of fatal liver damage in a baby whose mother had regular PA intake in pregnancy. [2] See pregnancy and breastfeeding safety.
• Breastfeeding: MSK advises against use. [1] The EU committee says children are particularly vulnerable to PAs. [2]
• Infants and nitrates: a Spanish study of 78 infants with diet-induced methemoglobinemia (a blood disorder that stops blood carrying oxygen well) found a clear link with borage purées; borage had the highest nitrate level of the vegetables tested (average about 3,968 mg per kg). Purées kept more than 24 hours and breastfeeding were also associated. [9]
• Foxglove mix-ups: case series describe people who ate leaves from a plant supposed to be borage and were treated for digitoxin poisoning, with nausea, vomiting and heart-rhythm changes; they recovered. [7][8] Do not forage or use a plant you cannot identify with certainty. See foxglove and plant and mushroom poisoning.
• Allergy and surgery: the sources we read do not describe an allergy or surgery warning specific to borage; because of the bleeding question and liver concerns, tell the surgical team about any borage oil. See supplements before surgery.

Official statements

• EU HMPC, 24 November 2014: a public statement on herbal medicines containing toxic, unsaturated PAs lists borage among PA-producing plants and says liver toxicity of these PAs is established. [2]
• EU food rules: according to a 2023 paper, maximum PA levels for foodstuffs including borage apply from 1 July 2022. [10] We did not read the regulation itself.
• German Federal Health Agency (as reported by MSK): recommends no more than 1 microgram of unsaturated PAs a day. [1]
• A borage herbal monograph from EMA: not found in the sources we read.

Related pages

• Pyrrolizidine alkaloids: comfrey, coltsfoot and borage
• Evening primrose, borage and GLA oils
• Evening primrose
• Comfrey
• Foxglove
• Herbs and liver injury