Green’s Dictionary of Slang

pellet n.

1. (drugs) a capsule of LSD.

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

2. (UK drugs) a capsule of amphetamines.

[Scot](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.