The incidence of opportunistic infections after thermal injury is high. Since 1985, we have been practicing Candida prophylaxis using nystatin "swish-and-swallow" and topical therapy. Patients treated between 1980 and 1984 served as controls and received no Candida prophylaxis. Although mean burn size, full-thickness injury, and age were comparable, the incidence of Candida colonization (26.7% vs 15.6%), infection (21.3% vs 10.0%), and sepsis (12.2% vs none) was significantly different between control and nystatin-treated groups, respectively. With prophylaxis, the incidence of Candida wound infection has been significantly reduced, and systemic candidiasis has been eradicated, eliminating the need for toxic systemic antifungal agents.