Rhuludian crystal
Rhuludian crystals were a form of narcotic chemical commonly sought out in the Delta Quadrant. 

In 2373, Chakotay and Tom Paris were offered the chance to purchase some from Sutok, a trader at Bahrat's space station near the Nekrit Expanse. He told them that ingesting only one of the crystals would make days of tedious travel seem like moments of exquisite rapture. Chakotay and Paris immediately turned down the offer. ()

de:Relubianischer Kristall
Drugs