There is an increasing problem in the world of toxicological evaluation in that, while test results of new compounds are appearing regularly, traditional methods of analysis of such data are cumbersome and slow. The new computer program CASE (computer automated structure evaluator) was designed to handle just such problems. It analyzes molecules and their associated biological activity on the basis of structural fragments found and identified by the program as being important for the activity based on statistical tests of significance. The program was used to examine mutagenicity in Salmonella typhimurium strains TA98 and TA100 (with S9 activation) of approximately 80-100 aromatic amines. The resulting structural features were then used in a predictive fashion to test the expected mutagenic properties of a smaller set of about 20 compounds. (Copyright 1985 Alan R. Liss, Inc.)