Green’s Dictionary of Slang

(drugs) heroin.

1959		J.E. Schmidt Narcotics Lingo and Lore.
1995		J. Stahl Permanent Midnight 348: You never heard ’bout ‘Aunt Hazel’. That’s what all the cats used to call it [i.e. heroin].
2001		ONDCP Street Terms 2: Aunt Hazel — Heroin.