racehorse charlie, n. — Green’s Dictionary of Slang

racehorse charlie n.

[var. on horse n. (7); though note charlie n.⁷]

(drugs)

1. any narcotic drug.

1936		D. Maurer ‘Argot of the Und. Narcotic Addict’ Pt 1 in AS XI:2 125/2: racehorse charlie. Morphine, heroin, or cocaine.
1942		Berrey & Van den Bark Amer. Thes. Sl.
1953		Anslinger & Tompkins Traffic In Narcotics 314: Racehorse Charlie. Morphine, heroin, or cocaine.
1959		J.E. Schmidt Narcotics Lingo and Lore.
2001		ONDCP Street Terms 17: Racehorse charlie — Cocaine; heroin.

2. a morphine user.

1959		J.E. Schmidt Narcotics Lingo and Lore.
1975		Hardy & Cull Drug Lang. and Lore.