Herb library · Spice · Citrus × paradisi
Grapefruit (peel)
A large, bitter-sweet citrus fruit whose dried peel is sold for teas and flavoring. The fact to know is that grapefruit, including its peel, can change how much of many common medicines reaches your blood, sometimes dangerously. The FDA requires warnings about it on some drug labels.
Serious warning
Grapefruit and its juice can raise the blood level of many common medicines, including some statins, blood pressure drugs, transplant drugs and heart-rhythm drugs, and lower others. The FDA requires some drug labels to warn against grapefruit; too much statin in the blood, for example, raises the risk of muscle and liver damage. Parts of the fruit other than the juice, including the peel, cause it too.
Traditional use
The fruit and juice are a breakfast staple, and the peel is candied, used in marmalade and dried for tea; a 2022 review notes grapefruit peel oil used in aromatherapy and its limonene in cosmetics. Grapefruit seed extract is sold separately as a natural antimicrobial.
What studies show
- Established
Drug interactions: grapefruit juice and grapefruit block an enzyme in the gut (CYP3A4) that breaks down many medicines, so more of the drug enters the blood; for a few drugs it has the opposite effect and less gets in. The FDA describes this for some statins, blood pressure drugs, transplant drugs, anti-anxiety drugs, heart-rhythm drugs and others.
- Limited
The peel: in a randomized crossover trial, an extract of the parts of the fruit OTHER than the segments (peel, pith and membranes) raised blood levels of the blood-pressure drug felodipine about threefold, as much as the juice did. The authors concluded that concern should extend to whole fruit and possibly candies made from grapefruit peel; a lab study found a CYP3A4-blocking compound in the peel.
Be careful of
Cautions
- InteractionIf you take any prescription or over-the-counter medicine, ask your pharmacist whether grapefruit affects it before using grapefruit peel tea or eating grapefruit. The FDA notes the effect varies with the person, the drug and the amount.
- InteractionThe FDA says Seville oranges, pomelos and tangelos might have the same effect. Avoid them too if your medicine interacts with grapefruit.
- NoteGrapefruit SEED extract is not grapefruit peel. Lab tests of products sold as grapefruit seed extract found synthetic disinfectants (benzethonium chloride, sometimes triclosan) and, in three products tested in Sweden, no real grapefruit extract at all; a couple on warfarin who took one had a dangerous rise in their clotting test.
- 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.
Sources
- Grapefruit Juice and Some Drugs Don't Mix (FDA Consumer Update) (opens in a new tab) · FDA · read September 25, 2026
- Grapefruit-felodipine interaction: effect of unprocessed fruit and probable active ingredients (Clin Pharmacol Ther, 2000) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Identification of epoxybergamottin as a CYP3A4 inhibitor in grapefruit peel (Eur J Clin Pharmacol, 2003) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Outgoing and potential trends of composition, health benefits, juice production and waste management of the multi-faceted Grapefruit Citrus × paradisi: A comprehensive review (Crit Rev Food Sci Nutr, 2022) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Adverse effects by artificial grapefruit seed extract products in patients on warfarin therapy (Eur J Clin Pharmacol, 2007) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
- Simultaneous identification and quantification by liquid chromatography of benzethonium chloride, methyl paraben and triclosan in commercial products labeled as grapefruit seed extract (Pharmazie, 2007) — PubMed record (opens in a new tab) · NIH · read September 25, 2026
Reviewed September 25, 2026.