The aim of the safety analysis performed by Chinoin Drug Safety Unit was to summarise the safety profile of NO-SPA (drotaverine hydrochloride), the Hungarian spasmolytic well known in Hungary and abroad. Authors collected the safety data from clinical studies between 1964-1998 for the determination of the adverse event frequency. Based on the data of 12111 patients treated with NO-SPA in 37 clinical trials 0.9% frequency of adverse events was found. The value indicates uncommon (0.1-1%) adverse event frequency according to the criteria for frequency categories. The benefit-risk ratio of NO-SPA is favourable, since the therapeutic effect does not include frequent adverse reaction occurrence.