Necrotic enteritis was produced in 4-week-old chickens with bacteria-free crude toxins of Clostridium perfringens. Typical gross lesions could be seen as early as 3 hr after intraduodenal infusion of toxin was begun. Early microscopic lesions were observed at 20 minutes, progressing with time to involve most of the mucosa. Death was related to the amount of toxin administered. Because systemic absorption of toxin is likely, acutely affected birds may die from toxemia.