The text presents results of the “Debata” prevention programme field research, which turns out to be the most popular proposal in Poland for V-VI grade primary schools pupils (over 52k participants according to the Report on the State of Drug Addiction of KBdsPN for 2020). Prevention research clearly seeks an effective impact, but this needs to be empirically proven. Analysis of the results obtained allows us to conclude that the programme is working as intended (attitudes and behaviour).