[nineplay]

Sherlock Holmes did not use opium. Watson once described him as appearing as someone under the influence of opium, but discarded the suggestion. In another story ( The Man with the Twisted Lip ) Watson discovers Holmes in an Opium den, but Holmes is on a case and in disguised.

The cocaine habit is probably exaggerated. Watson does not give a frequency of his usage and reports Holmes as saying that he only uses it when he doesn't have a case to occupy his mind. Whether this means he uses it a few times a week or a few times a year is not stated.

[0xBDB]

It's strongly implied that Holmes used morphine for recreation as well by the fact that Watson had to ask which habit he was indulging in The Sign of the Four.

"Which is it today," I asked, "morphine or cocaine?" "It Is cocaine," he said, "a seven-percent solution. Would you care to try it?..."