Drug

A drug was a general term for a form of medicine. Drugs could have many beneficial uses, they could be used to cure, treat and sedate. (TV: The Daleks, The Edge of Destruction) They could also be used recreationally like LSD and were often addictive like hashish and vraxoin. (PROSE: Dead Romance, TV: Marco Polo, Nightmare of Eden) A subsection of these recreational and often religious drugs were hallucinogenic drugs. (PROSE: The Left-Handed Hummingbird)

Drugs could also be used to assist transformation; into Cybermen and in addition to mutation; Daleks. (TV: Attack of the Cybermen, AUDIO: The Time of the Daleks)

Development
Many drugs that were in development were so new that their properties were unknown, only in combination could they function in a useful manner. (TV: Doctor Who and the Silurians)

Pharmaceutical companies regularly tested drugs, often on animal subjects to test the effectiveness of their drugs. (PROSE: Warlock)

Addiction
Excessive use of drugs could lead to drug addiction, this was often the result of use of illicit drugs. (PROSE: Unnatural History