Vraxoin (also known as XYP or "vrax") was a dangerous, addictive drug. It was a grey, ash-like powder that also appeared as a sparkly gold powder (possibly the refined form) which could be taken orally. It was discovered on the Cygnus Rim around 1999; it was consumed by "snorting" the substance. (PROSE: Christmas on a Rational Planet) The drug caused a drunken effect and apathy, then extreme anger during withdrawal. (TV: 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. (PROSE: Mean Streets) The Fourth Doctor mentioned it had caused chaos on several planets, even stating he'd seen planets virtually ruined by Vraxoin.
Vraxoin was originally made from a type of fungus, but in order to finally solve the vraxoin problem, officials incinerated the entire planet on which the only known source existed. This eliminated vraxoin trade for some time, until a second source — the Mandrels — was located by a zoologist named Tryst on the planet Eden. Although he disliked the necessity, Tryst became a Vraxoin manufacturer and dealer in order to fund his experiments, disgusting the Fourth Doctor when he discovered what Tryst was doing. (TV: Nightmare of Eden)