Purpose The purpose of this paper is to present the results and context of the drug checking service (DCS) performed by the harm reduction project Échele Cabeza (EC) in Colombia. Design/methodology/approach Data from several years are presented with a focus on data from 2021. In 2021, data were derived from 2,339 questionnaires filled out by DCS users and a total of 2,868 drug checking test results from samples collected at the fixed-site service in Bogotá and 30 music festivals in 8 cities nationwide. Findings The tusi phenomenon is gaining strength in Colombia revealing a problem associated with the changing makeup of tusi and, thus, polydrug use. MDMA adulteration and misrepresentations have increased in comparison to 2019. There is an increasing number of people who want to use the DCS in Colombia, which is encouraging but also exposes the limitations of the drug checking methods available to EC. Originality/value This paper offers the first publication of the pioneering drug checking organization EC in Latin America.