In the fried meat surface layer (the meat crust) mutagenic heterocyclic amines are formed during cooking. A human cancer risk is conceivable after intake of such mutagenic activity. We investigated the current literature mentioning fried foods, and six studies of colorectal cancer, three of stomach cancer and one each of cancer of the breast, lower urinary tract and pancreas are included. None of the reports tried to assess directly the intake of mutagenic activity from the fried surface. One indirect measure of mutagenic activity is to look at the browning of the meat surface; two investigations are available for this variable. The content of mutagenic activity in the surface may vary with the 'doneness' of meat and two studies consider this variable. Another indirect measure is to compare results from meat irrespective of cooking methods (ie, comparing meat not fried with fried meat or fried foods). There are several validity problems in the reviewed studies. Major potential sources of bias include, quite apart from misclassification of mutagenic activity, possible confounding factors from meat per se and fat. The epidemiological evidence in the field is sparse and cannot justify preventive measures.