Clindamycin
"I was prescribed cleocin (clindamycin) for an infected tooth.  I have never had this antibiotic before, called the pharmacist and was told to drink a lot of water because it has a tendency to cause diarrhea.  Well I stayed on it for five days while enduring terrible stomach cramps and uncontrollable diarrhea until I came to my senses.  I called the dentist and switched to augmentin which did the trick.  Now, ten days later, I'm still recovering from the side effects of the cleocin.  I will never take this antibiotic again.  There are too many alternatives to endure these reactions, let alone the fact that this drug strips your body of probiotics that affect the colon and can cause serious, and yes, even fatal consequences."