Interesting history/medicine/science - why some meds have warnings about grapefruit - "Grapefruit has a high volume of compounds called furanocoumarins, which are designed to protect the fruit from fungal infections. When you ingest grapefruit, those furanocoumarins take your cytochrome P450 enzymes offline. There’s no coming back. Grapefruit is powerful, and those cytochromes are donezo. So the body, when it encounters grapefruit, basically sighs, throws up its hands, and starts producing entirely new sets of cytochrome P450s. This can take over 12 hours... And it does not take an excessive amount of grapefruit juice to have this effect: Less than a single cup can be enough, and the effect doesn’t seem to change as long as you hit that minimum."