A lot of Jazz swing musicians smoked reefer for inspiration,to play "hot", Bix Beiderbecke was no exception. The book Remembering Bix has many examples. Here are just a few:
In Chicago we found George Johnson, Bix and Vic Moore in a hotel room, all primed for a big night. Bix sleepy-eyed said "We got the mixings." "A couple of quarts of gin and a package of Muggles. Its enough to start" said Gene Fosdick. - page 90
As I'd anticipated, they sounded much better in person than on the record. For half an hour or more they continued warming up their chops, Muggles were rolled, lighted, and passed around; some of the guys were drinking and blowing gage, and were soon feeling no pain. - page 120
They played on, tune after tune; in between they drank alcohol & orange juice, or homebrew, or passed a joint around. - page 124
Someone had lit up a joint. Bix handed it to me in my turn remarldng "Hell he's usually with the band anyhow, he might as well get high!" - page 275
Between sets, also, they would meet outside the pavilion, usually out back behind the dunes leading down to the beach, to pass a joint around. I should add parenthetically that the "tea" available in those pristine days, at fifteen cents a joint was of such quality and vigor that five or six souls could pass just one of those around, each getting perhaps four good pokes out of it before it reached the tweezers stage, and all five or six be flying like kites within five or six minutes- and stay stoned and flying like that for a couple of hours, sometimes longer, depending on circumstances. By the way my recollection is that grass wasn't even illegal in Chi when I was a boy, only because the fuzz hadn't caught on yet to its existence among us- I don't know that any body knew about or smoked it then except musicians and their friends. I believe it all came from Mexico, and it was dynamite. but friendly dynamite, giving you usually a laughing high. - page 247
Remembering Bix also has references to Bix smoking Marijuana on page 276, Page 3 and Page 389 have references to Louis Armstrong's arrest for Marijuana.
(Remembering Bix, Ralph Barton. c 1974 Harper & Row, Publishers)
Others disagree with Ralph Barton's account that Bix used cannabis.
TED GOTTSEGEN: I hate to brake the bad news to you, but Bix was not a pot head. The book "The Leon Bix Beiderbecke Story" that myth is put the rest with several eye witness accounts of Bix the man and musician, including an interview with his brother who, while admitting Bix's drinking problem, emphatically denies that his brother smoked pot. Don Murray, a former bandmate further testifies that Box never smoked pot because he felt that it hindered you from making good music and the he never touched marijuana and didn't like playing with people who did. Prohibition was in full swing during this period and most of these guys chose gin as their poison.