A method of prediction of biological activities of chemicals has been developed as a new drug-discovery technology. In recent years, a wide distribution of non-controlled psychotropic substances has become a serious problem in Japan. It takes a long time to evaluate their bioactivity in vitro and in vivo. Computer simulation could regulate new designer drugs in a short time. Prediction of biological activities of these drugs was performed by quantitative structure-activity relationship (QSAR) and pharmacophore-fingerprint method. A preliminary demonstration to predict the bioactivity of 4-methcathinone, a cathinone derivative that is widely distributed, by two methods is described herein.