Yikes! I'm OK with penicillin, but am allergic to sulfa antibiotics (like Bactrim). They said I got drug-induced lupus from it, with a rash and joint pain (went away once it got out of my system). H recently had to take it for a staph infection and I was afraid to let him kiss me or anything. Oh, and I had to give it in liquid for to one of my guinea pigs years ago--I wore latex gloves when I administered it to be safe.