The effects of red chilli were examined in 12-w-old male Wistar rats fed a commercial diet mixed with ground Capsicum frutescens L fruits at levels of 2% and 10% (w/w) for 8 w. When compared with controls, the general health, body weight gain, feed intake and feed efficiency were not adversely affected on the rats on feed with 2% Capsicum, while the feed intake and growth rate were depressed and exfoliation of the intestinal epithelium into the lumen and cytoplasmic fatty vacuolation and necrosis of the centrilobular hepatocytes occurred in rats at 4 and 8 w on feed with 10% Capsicum. This correlated with changes in hematology, serum enzyme profiles and other serum constituents.