A variety of cutaneous and systemic adverse reactions related to procedures of in vitro fertilization (IVF) have been reported, among them skin reactions secondary to LHRH agonists--attributed to nonspecific histamine release--and a serum sickness-like syndrome which appears to be related to heterologous sera contained in the rinsing solution for graafian follicles. We report here the case of a 41-year-old woman who on two occasions suffered from clinical features consistent with serum sickness after being submitted to current IVF protocols. A specific IgG-mediated reaction against bovine serum albumin (BSA) was demonstrated. The avoidance of BSA or other heterologous sera in the rinsing solutions for graafian follicles is advisable in all IVF protocols, since it adds an unnecessary risk of developing immune complex-related illness.