Green’s Dictionary of Slang

1. (drugs) a capsule of LSD.

1969		R.R. Lingeman Drugs from A to Z (1970).
1971		E.E. Landy Underground Dict. (1972).
2001		ONDCP Street Terms 16: Pellets — LSD.

2. (UK drugs) a capsule of amphetamines.

1973

(con. mid-1960s) J. Patrick Glasgow Gang Observed 124: Four to six pellets would be taken together and washed down with cheap wine or beer.