cocaine

In the 19th century, cocaine was being considered for medical purposes.

Sigmund Freud supported the use of cocaine as an anti-depressant, even publishing a manuscript detailing its virtues, although he later changed his position and came out against the drug.

In fact, the only person to stand against the use of cocaine then was Sir Arthur Conan Doyle, who depicted its destructive qualities in his fictional detective, Sherlock Holmes.