I'm not buying the whole story. My understanding of garlic is that it is one hell of a potent detoxifier of various sorts of sludge in your body. The more toxic waste you have, the worse your reactions to garlic would be. As they say in some eastern culture, I can't remember which, garlic "makes you angry". Well, yes & no. What it's doing is stirring up old crap stored in the body and an already overworked liver can't handle it. Anger and an overworked, stagnant liver go together, as traditional societies have known for aeons.

So, it would seem to be that if garlic does this to you, it means you need a cleanout of one sort or another. It could be said, therefore, that garlic is a diagnostic tool.