In June 2018, regulatory agencies became aware of contamination of the active substance valsartan with N-nitrosodimethylamine (NDMA). After initial analyzes was discovered thath the group of drugs found to be affected is angiotensin II receptor blockers, which have a tetrazole ring in their structure. As NDMA is a possible human carcinogen, a series of drugs has been withdrawn worldwide, as well as in the Republic of Croatia. What the withdrawn batches of drugs had in the first moments in common is active pharmaceutical ingredient manufactured by Zhejiang Huahai Pharmaceuticals (ZHP), Linhai, China. It was later shown that the change in their manufacture process led to contamination with NDMA, but the mentioned event was the beginning of a review of the current pharmaceutical practice and evaluation of synthetic processes. Shortly after the discovery of NDMA, N-nitrosodiethylamine (NDEA) and other nitrosamines were detected in various concentrations in individual batches of sartans, metformin, and ranitidine. Therefore, it was necessary to determine the possible causes of nitrosamine and the risk to which patients were potentially exposed. Permitted maximum levels of detection and quantification have been published, and methods for the analysis of nitrosamine contaminants have been developed, a deadline is given for the manufacturers of the active pharmaceutical substances concerned and the marketing authorization holders within which they must review to carry out a risk assessment and ensure the existence of batch control strategies for the active pharmaceutical substance.This paper lists potential ways of creating nitrosamines in drugs according to the information available on the websites of regulatory agencies such as the EMA, FDA, Swissmedic and so on. The impact of nitrosamine contaminants on the supply of the market of the Republic of Croatia is also presented, and the terms important for understanding the paper are explained.