Doctors have warned of a "lack of knowledge" about the dangers of mixing some medications with grapefruit.
The fruit can cause overdoses of some drugs by stopping the medicines being broken down in the intestines and the liver.
The researchers who first identified the link said the number of drugs that became dangerous with grapefruit was increasing rapidly.
They were writing in the Canadian Medical Association Journal.
The team at the Lawson Health Research Institute in Canada said the number of drugs which had serious side effects with grapefruit had gone from 17 in 2008 to 43 in 2012.
They include some drugs for a range of conditions including blood pressure, cancer and cholesterol-lowering statins and those taken to suppress the immune system after an organ transplant.
Chemicals in grapefruit, furanocoumarins, wipe out an enzyme which breaks the drugs down. It means much more of the drug escapes the digestive system than the body can handle.
There's been a lot of coverage in the medical community up here about the dangers of grapefruit/grapefruit juice for at least 15 years.
That BBC article Izzy linked also mentioned Seville oranges, and the fact they are used in a lot of marmalades.
Interactions between grapefruit juice and medications have long been recognized. Last year, the Medical Letter on Drugs and Therapeutics devoted an entire issue to grapefruit juice and the dangerous drug interactions that can result. The U.S. Food & Drug Administration requires all prospective new drugs that are thought to interact with this enzyme system to be tested for interactions with grapefruit juice. And a warning about grapefruit juice is included in the “food-drug interactions” that come with dozens of medications.
Drugs that use the same pathway and interact with grapefruit juice target some of the most common health problems doctors see today. The list consists of more than 50 medications, including some drugs used to treat high cholesterol, depression, high blood pressure, cancer, depression, pain, impotence, and allergies.
Karch notes that interactions with grapefruit juice are well known and documented among drug researchers, and that an appropriate warning label is included with each prescription. Nevertheless, she says that many patients, nurses and doctors aren’t aware of the interactions or the potential serious consequences, and that many people fail to read the warning labels about drug-food interactions.