Unsaturated free fatty acids (FFAs), such as palmitoleic, oleic, linoleic, linolenic and arachidonic acids, haveinhibitory actions on mutagenesis. These FFAs in bile may play a role in preventing cholecystopathy and theirlevels may be influenced by diet. However, the effects of dietary intake on biliary FFAs levels is not known. Inorder to examine possible associations between dietary habits and biliary FFAs levels, bile samples were collectedfrom resected gallbladders of 114 Chilean female patients with gallstones, and FFAs were measured with anHPLC system. The long-term dietary intake of the patients was investigated through a semi-quantitative foodfrequency questionnaire. A high intake of vegetables was negatively correlated with the total FFA level (r = -0.264, P = 0.010). Positive correlations were found between fruit consumption and the lauric acid level (r =0.200, P = 0.041), fish consumption and the levels of oleic (r = 0.370, P <0.0001), linolenic (r = 0.197, P = 0.038)and arachidonic (r = 0.200, P =0.035) acids, and consumption of foods fried in vegetable oil and the linoleic acidlevel (r = 0.269, P =0.004). Linoleic, linolenic, and arachidonic acids which may have an inhibitory effect onactions of unknown mutagens in bile appear to be increased by consumption of high levels of fish and friedfoods.