Cocaine was recommended and prescribe for much more than anesthetic.
the other two also have medical use cases.
the "war on drugs" did much worse than the substance themselves.
drugs don't ruin lives, but people who ruins their lives might use drugs.

Cocaine used to be an anesthetic and it was in coke cola 

Bell_curve

science

What has been the worst or most harmful scientific discovery of all time?

Taft

Hard drugs like meth, cocaine, heroin. These things ruin so many lives and I wish they were never discovered/created. Hoping for those addicted to recover.