A man experienced a toxic reaction after being stung simultaneously by 175 yellow jackets. After an initial minor anaphylactoid shock he presented a delayed acute renal failure secondary to intravascular hemolysis and rhabdomyolysis. He completely recovered without sequellae after hemodialysis. A second clinical case of hymenoptera venom-induced toxic reaction is presented. A woman was stung by 65 bees at the same time and she only had minor symptoms of anaphylactoid shock associated with an extensive angioedema. No symptom of acute renal failure, myolysis or hemolysis could be detected.