I have spoken about some of the nasty diet pill side effects before but they are worth repeating. Ali has one of the well known ones, diarrhea. Wouldn't it be wonderful to show off that brand new dress you could now fit into except that brown stain that appears after you got up from your chair. Ali was jokingly referred to as the pill that gave you a workout (making you run to the bathroom).
Another diet pill worth staying away from was those fat inhibitor pills. I think most of them have been taken off the market now but they might still be a few bottles out there. What they do is coat your stomach and intestine so you could not absorb fat, of course you would also not absorb much of anything else either. Another pill to give you the runs, runs to the bathroom that is.
Diet pills are best left to be prescribed by your doctor and not left for picking and choosing off of the shelf at the grocery store.