The confirmed cia program to start the crack epidemic and use it to profit off of and impoverish black communities in the US. Read gary webb - dark alliance for more on that.
The historical and still ongoing spread of alcohol to native communities in the US.
The CIA pretty much took over the majority of international drug trade after ww2 via the helliwell plan(modelled on Chiang kai-sheks program) , and used it to fund their covert ops. A lot more on that in williams - operation gladio.
A few other related ones: