Vraxoin

Vraxoin (also known as XYP or "vrax") was a dangerous, addictive drug. It was a grey, ash-like powder which could be taken orally. The drug caused slightly drunken affect and apathy, then extreme anger during withdrawal. (DW: Nightmare of Eden) Vrax-users (also known as Vrax-Heads) were also known to become shaky and to lose strength and concentration after taking the drug. (BNA: Mean Streets) The Fourth Doctor mentioned it had caused chaos on several planets. (DW: Nightmare of Eden)

Vraxoin was made from a type of fungus, but the planet it was grown on was fire-bombed. It could also be harvested from the bodies of dead Mandrels, who disintegrated into Vraxoin if killed by electrocution. (DW: Nightmare of Eden)