Drovian zwil was a potent variation of the drug zwil, produced on Algara II. The Drovians were one of only a few species to find the original form addictive, and produced this stronger version to suit their needs.[1]
The Shistavanen spicelord Volven Roxe, in charge of the Outlander Club on Coruscant, was addicted to this drug, although he never traded it himself.[1]