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. It was discovered on the Cygnus Rim around 1999, it was consumed by snorting the substance. (NA: Christmas on a Rational Planet) 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 In order to finally solve the vraxoin problem, officials incinerated the entire planet on which the only known source existed. However it could also be harvested from the bodies of dead Mandrels, who disintegrated into Vraxoin if killed by electrocution. (DW: Nightmare of Eden)