What is the origin of the phrase "dope cart"?

I ran across a statement in a personal memoir that I was reading the other day that seemed odd to me and I wanted to know if anyone here had any idea of the etymology of the phrase. The person was talking about their working life inside a southern textile mill and referred to a person who sold drinks and snacks to the workers there as “running a dope cart”. Given the usual connotation of the word “dope”, this seems incongruous. Anyone with ideas?

I personally think it was more Southern US slang.

Sounds related to the guy who travels around the hospital dispensing drugs to me. Either that or the snack guy is actually selling drugs from his snack cart. Neither of which would suprise me.