The fact that you don't distinguish between categories of drugs is, no offence, a major indicator of ignorance in the subject matter. Hallucinogens are not stimulants are not depressants are not dissociatives are not alcohol.
If you mean "illegal drugs", do you really think that the objective, scientific threshold between harmful and harmless is legality?
You are free to do whatever you want, it's your body. But perhaps learn more about something you don't know anything about before passing judgement.