Green’s Dictionary of Slang

1. (US) in pl., aperient pills or medicines, used to cure constipation.

1909		J. Moss Officer’s Manual 284: Openers. Cathartic pills [HDAS].
1931		Irwin Amer. Tramp and Und. Sl. 139: Openers. Cahartic pills.

2. (US) a jemmy.

1949

Monteleone Criminal Sl. (rev. edn).