I had bronchitis. The first antibiotic my doc had me on put me in the ER 20 minutes after I took it (severe allergic reaction...irregular heartbeat...trouble breathing...you know, the fun stuff!) So he put me on something else. You know how you're told to finish ALL of an antibiotic, even if you feel better, or the whatever-it-is could come back? Well, I didn't listen (actually I just forgot about taking them once I felt better.); now my bronchitis is back. Damn it.