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Grapefruit and medicines: what the evidence says

A healthy fruit with one serious catch: it changes how the body handles certain medicines. It is the best-documented food-drug interaction there is. The fat-burning claims are not supported.

By the editors of Alimentotherapy Last reviewed October 18, 2026 4 min read Not medical advice

Grapefruit

Citrus x paradisi

Best-supported use: Interacts with many medicines

EvidenceStrongbest use

The short answer

Grapefruit and its juice block an enzyme in the gut wall (CYP3A4) that breaks down many medicines, so some drugs, including certain statins and the blood pressure drug felodipine, reach much higher levels in the blood; the FDA requires warnings on affected drugs FDA; Bailey 1991. The effect can last for days after a glass of juice, so spacing the juice and the pill apart does not reliably avoid itTakanaga 2000.

The evidence, use by use

Each claim graded on human studies only. How we grade

Use	Grade	What the research found
Raises blood levels of some medicines (an interaction, not a benefit)	Strong	In the 1991 study that found the effect, felodipine taken with grapefruit juice reached on average 284 percent of its level with water, with lower blood pressure, faster heart rate and more side effects. Orange juice had no such effect. Bailey 1991; FDA
Weight loss	Limited	In one 12-week trial of 91 adults with obesity, half a fresh grapefruit before meals led to 1.6 kg weight loss versus 0.3 kg with placebo. The idea that grapefruit burns fat by itself is not supported. Fujioka 2006

Which kinds of medicines are affected

The FDA lists these as examples of drug types where some, not all, members interact with grapefruitFDA:

Examples from the FDA's consumer update on grapefruit juice

Drug type	Examples named by the FDA
Some cholesterol-lowering statins	Simvastatin (Zocor), atorvastatin (Lipitor)
Some blood pressure drugs	Nifedipine (Procardia, Adalat CC)
Some anti-rejection drugs after transplant	Cyclosporine (Neoral, Sandimmune)
Some anti-anxiety drugs	Buspirone (BuSpar)
Some corticosteroids for Crohn's disease or ulcerative colitis	Budesonide (Entocort EC, Uceris)
Some heart rhythm drugs	Amiodarone (Pacerone, Cordarone)
Some antihistamines (the effect is reversed: less drug gets in)	Fexofenadine (Allegra)

With most affected drugs, the juice lets more of the medicine into the blood, which raises the chance of side effects. With certain statins, too much drug can mean a higher risk of liver and muscle damage. With fexofenadine the opposite happens: grapefruit, orange and apple juice block a transporter, so less drug is absorbed and it may not work as well FDA.

How strong the interaction is varies from person to person, because people carry different amounts of the enzyme in their gut, and with the drug and the amount of juice FDA. That is why the only reliable answer comes from your pharmacist or the leaflet for your specific medicineFDA; Bailey 2013.

Why spacing it out does not work

Grapefruit does not just compete with a drug in the stomach. In a study where volunteers drank grapefruit juice three times a day for a week, the drug nisoldipine still reached higher blood levels when taken up to 72 hours after the last glass, and the authors concluded the effect lasted at least three daysTakanaga 2000. If your medicine interacts, the safe plan is to avoid grapefruit, not to time it.

Other fruits that act the same way

Safety

Seville oranges (the bitter kind used in marmalade), pomelos and tangelos may have the same effect as grapefruit. If your drug interacts with grapefruit, avoid those too, and check the labels of mixed juices and fruit-flavored drinks for grapefruit FDA. Ordinary sweet oranges did not affect felodipine in the original study Bailey 1991.

If none of your medicines is affected, grapefruit is simply a good fruit: the FDA notes it supplies vitamin C and potassium FDA.

Before you try it: safety and interactions

Who should avoid it or ask first

You take a medicine whose label or leaflet warns against grapefruit, including some statins, calcium channel blockers, cyclosporine, buspirone, budesonide and amiodarone.
You are starting a new prescription: ask the pharmacist whether grapefruit, Seville oranges, pomelos or tangelos are a problem with it.

Possible side effects

No particular side effects as a food for people not taking an affected medicine.
With an affected medicine: too much or too little drug in the blood, and the side effects that follow.

Pregnancy and breastfeeding

Grapefruit is a normal food in pregnancy. The same medicine interactions apply. FDA; Bailey 2013

Medicine interactions

Check another food or medicine in the interactions list.

Common questions

Can I eat grapefruit if I take a statin?

It depends on the statin. The FDA names simvastatin and atorvastatin as examples of statins that grapefruit can affect, raising blood levels and the risk of muscle and liver damage, but not all statins interact. Ask your pharmacist about your specific drug.

How long after grapefruit can I take my medicine?

Spacing them out does not reliably help. In a study of the blood pressure drug nisoldipine, grapefruit juice still raised drug levels when the pill was taken up to 72 hours after the juice, and the effect lasted at least three days. If your medicine interacts, avoid grapefruit.

Do oranges interact with medicines like grapefruit?

Ordinary sweet oranges did not affect felodipine in the original 1991 study, but the FDA says Seville oranges, pomelos and tangelos may act like grapefruit. Orange and apple juice can reduce absorption of the antihistamine fexofenadine.

Sources

Primary research and government sources, each checked on the date this page was reviewed.