Green’s Dictionary of Slang

Owsley acid n.

also Owsley, Owsley’s acid, white Owsley’s
[Augustus Owsley Stanley III (b.1935), the best known of all LSD chemists. His ‘own-brand’ drugs were considered the very best]

(drugs) LSD.

[US]T. Wolfe Electric Kool-Aid Acid Test (1969) 212: In fact Owsley’s acid was famous internationally. When the acid scene spread to England [...] the hippest intelligence one could pass around was that one was in possession of ‘Owsley acid’. [...] The heads rapped over Owsley blues like old juice heads drawling over that famous onetime brand [...] Fairfax County Bourbon.
[US]E.E. Landy Underground Dict. (1972) 144: owsley [...] Highest-quality LSD.
[US]D.E. Miller Bk of Jargon 338: Owsley: Popular purple California LSD during the 1960s.
[US]ONDCP Street Terms 16: Owsley [...] Owsley’s acid — LSD. [Ibid.] 22: White Owsley’s — LSD.