D: Grapefruits are out to get me.

Y: Excuse me?

D: Grapefruits, I said. They're after me.

Y: Ok Don, just take it easy. I'm going to make a phone call and some nice men in white coats are going to come and make you all better.

D: I'm not crazy, Yael. It's just that I used to love eating grapefruit and drinking grapefruit juice . . .

Y: And so . . .?

D: And now I've learned that grapefruit juice can be dangerous if you're taking certain kinds of medication.

Y: I don't follow.

D: It's like this. When you take a pill, your body uses enzymes to metabolize the drug and make sort of size it down so that it doesn't do more harm than good.

Y: So what does grapefruit juice have to do with it?

D: It turns out that grapefruit juice screws up the process. It only affects enzymes in the gut that help metabolize oral medication. But tests done by David Bailey of the London Health Sciences Center in Canada have shown that drinking grapefruit juice while taking drugs to control cholesterol, for example, can hamper the metabolizing process and allow too much of the drug to enter the bloodstream.

Y: It sounds like grapefruit juice can cause you to overdose even if you're taking the proper dosage.

D: Basically. It's not like every time you drink grapefruit juice and take medication this will necessarily happen, and it may not happen at all with some drugs. But grapefruit juice does mess with the how the body absorbs drugs some of the time, and the results can be dangerous. Overdosing on some prescriptions drugs can cause all sorts of problems, including a serious muscle disorder.

Y: So the moral here is, if you're on oral medication, avoid grapefruit juice.

D: Yep. Grapefruit juice may seem harmless, but medicine goes down best with a simple glass of water.