Opium
From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
Opium is a narcotic created from the sap of the opium poppy.
Opium den
An opium den is referred to directly by Doctor Sherman Cottle while talking to Cally (The Ties That Bind).
The Dive Bar is an establishment in pre-Fall Caprica City that combines a bar and an opium den (Rebirth).