Uh, that's a very simplistic headline that merits a big caveat:<p>> This interaction is particularly dangerous when the drug in question has a low therapeutic index, so that a small increase in blood concentration can be the difference between therapeutic success and toxicity.<p>Source: <a href="http://en.wikipedia.org/wiki/Grapefruit_juice_effect#Mechanism_of_the_interaction" rel="nofollow">http://en.wikipedia.org/wiki/Grapefruit_juice_effect#Mechani...</a>