Trihalomethanes (THMs) as the main disinfection by-products (DBPs) during the last four decades have concerned the public and scientific opinion for the possible carcinogenic effect on human health. The purpose of this paper is to investigate the disinfection of drinking water, types of DBPs and the formation of THMs. The formation of THMs during the chlorination process represents a serious health problem, as they significantly increase the possibility of the risk of several types of cancers. In this article we are discuss the health risk imposed by THMs, considered toxic and possible carcinogenic as well as mutagenic to the human
body. Thus, their elimination and regular monitoring is imperative. In this article we present the removal technologies for the THMs and their precursors. This article also provides the basic information related to the analytical methods for the determination of the THMs
