The 4-chloromethcathinone (1-(4-chloronyl)-2-(methylamino)-1-propanone), also known as 4-CMC or cledrone, is a synthetic p-chlorine substituted derivative of and belongs to the NPS (Fig. 1). It has been commercially available on the black market since 2014 and is sold via the Internet in the form of white powder [4, 7]. The 4-CMC is currently a controlled drug in Germany, China and Virginia (USA), but until today it has not been classified as an illegal substance in the Act of Counteracting Drug Addition in Poland [9, 10]. Due to the novelty of the drug, there is no data in scientific literature considering the rmacokinetics, rmacodynamics, rmacological and effects, and the potential of acute overdose effects and addiction in a long period of time. Wiergowski et al. reported three cases of 4-CMC intake. However, these inses were considered also with a high dose administration of 25B-NBOMe. Therefore, the patientsâ symptoms described by the authors were rather considered to be those by the 25B-NBOMe use, rather than by 4-CMC. Currently, the majority of information concerning the model of consumption of 4-CMC and its impact on the body originates from the anecdotal statements of users published on Internet forums Similarly to other synthetic cathinones, 4-CMC is typically snorted or ingested orally. Depending on the route of administration and the userâs tolerance, the dose of 4-CMC resulting in the desired effects ranges from 100 to 300 mg for oral ingestion and from 50 to 150 mg for snorting. Additionally, the effects of 4-CMC can be felt much faster after snorting than after oral ingestion (2â3 and 30â60 min, respectively), but they last for a shorter time. Also, the profile of effects of 4-CMC on the body depends on the route of administration; oral ingestion results in a euric effect, while snorting in a speed-like effect is accompanied by agitation, increased concentration, and increased self-confidence