Green’s Dictionary of Slang

(S.Afr. drugs) marijuana.

1977		P.C. Venter Soweto 153: A stranger to the tsotsi’s dangerous world could save his throat if he has some knowedge of basic words and phrases: Atshitshi – marijuana.
1979		A. Brink Dry White Season 84: You get one passed out from atshitshi: same thing.
1980		in J. & W. Branford Dict. of S. Afr. Eng. (1987).
2007		S. Banick Accidental Enlightenment 231: He enjoys puffing an afternoon bowl of dagga, known elsewhere in the world as atshitshi.