Ingestion of Enterolobium contortisiliquum pods causes digestive disturbances, secondary hepatogenous photosensitization and abortions in ruminants. Pods were administered to sheep via a ruminal cannula to characterize acute poisoning. In Experiment 1, a single dose of 12g/kg of body weight (BW) was administered to three sheep in one experiment. One sheep died, and the other two recovered after presenting clinical signs. In Experiment 2, 10g/kg BW were administered daily to 15 sheep until the onset of clinical signs or for three consecutive days. Fourteen sheep showed mild to severe signs after the ingestion of 1-3 doses. Two sheep died, and the others recovered. Clinical signs in both experiments were diarrhea, anorexia, rumen atony, apathy, dehydration and tachypnea. The main macroscopic findings were an orange, frothy ruminal content witch contained pods fragments. The intestinal content was liquid. Detachment of the mucosa from the submucosa and ballooning degeneration of mucosal cells were observed histologically in the forestomachs. Evaluation of ruminal contents revealed acute lactic ruminal acidosis (ALRA). Bromatological analysis of E. contortisiliquum pods revealed 537.8g/kg DM (dry matter) of non-fibrous carbohydrates, which is sufficient to cause ALRA. Only one sheep in Experiment 2 had liver failure, characterized by jaundice, elevated serum activity of liver enzymes and histological lesions in liver biopsies. It is concluded that the administration of E. contortisiliquum pods in forage fed sheep at doses of 10g/kg BW or higher may cause ALRA. The induction of liver failure in one sheep suggests that liver damage may occur in those sheep that do not develop acidosis.