We have evaluated hundreds of patients with a history of reactions to penicillin(s) (penicillin, amoxicillin, or related cephalosporins).  After evaluation and testing, more than 90% of these patients can safely take these drugs without fear of a severe allergic reaction. The testing occurs in two phases, skin testing and an oral challenge.  We first inject a small amount of the drug under the skin with a sterile needle and look for a mosquito bite-like reaction in 15 minutes.  This is called intradermal testing.  If this is negative a series of three oral doses of penicillin or related antibiotic will be...