Abstract Wistar strain albino rats were fed turmeric ( Curcuma longa L.) powder (100 mg rat −1 day −1) and its alcoholic extract (20 mg rat −1 day −1). The caecal contents were analysed after 3 months and 2 years. Colony counts of lactobacilli and total aerobes were decreased and of coliforms, total anaerobes and Clostridium perfringens were increased in the caecal contents of rats fed turmeric and its alcoholic extract for 3 months. A similar trend was also observed after 2 years feeding, except that the coliform count apparently decreased. Concomitantly faecal deoxycholic acid was increased and serum globulins were decreased as compared to those of rats fed a control diet.