The most serious and common untoward effects produced by penicillin are alergic reactions. Numerous death have occurred from anaphylaxis after the injection of penicillin.

• 例如：青霉素引起的最严重和最常见的不良反应是过敏性反应。注射青霉素后，由于过敏性反应导致死亡的事例为数很多。