A disease causing anorexia and ruminal indigestion in cattle and goats, and also edema of the lips, tongue and face in goats, was associated with the ingestion of Centratherum brachylepis in pastures containing large amounts of the plant. On 3 farms with a total of 217 cattle and 140 goats, 57 (26%) cattle and 56 (40%) goats were affected, and 11 (5%) cattle and 34 (24%) goats died. In one cow that died there were widespread and severe histologic lesions in the rumen that consisted of vacuolation and ballooning degeneration of keratinocytes, and vesicle and pustule formation in the epithelium. C. brachylepis was administered orally to 3 sheep and 11 goats. Clinical signs similar to those observed in spontaneous field cases in goats were reproduced in 2 sheep and 3 goats that ingested 30-50 g/kg body weight of the plant when administered within 48 h of it being collected. C. brachylepis collected between 2 and 13 days prior to being administered caused no clinical signs in 1 sheep and 8 goats at dose rates of 30-300 g/kg body weight of the plant. These feeding studies provide evidence that C. brachylepis is the cause of the field disease observed and that the plant loses toxicity after harvesting.