Green’s Dictionary of Slang

(drugs) Lebanese hashish, usu. qualified as Red Leb, Lebanese Gold.

1978		L. Kramer Faggots 301: Moroccan Hash, Red Lebanese, Black Afghani, Hawaiian, Kentucky Bluegrass.
1999		Indep. Rev. 19 Aug. 11: The skunk was pretty edgy [...] Whereas the Leb was heavy.