Whitey is a drug slang term for when a recreational drug user, as a direct or indirect result of drug use (usually cannabis), begins to feel faint. The term comes from the way one's skin turns pale during and after a fainting episode. While fainting is usually only a problem for those with low blood pressure, it can become possible for those without hypotension to faint after using cannabis or other drugs which have the short-term effect of lowering the blood pressure. Whiteying is perceived by the stoner subculture as the result of using too much cannabis within too short a period of time. In fact the factors that usually facilitate fainting, such as tiredness, lack of fluids and food, and a hot and humid environment, as well as natural hypotension, are just as important as the amount of cannabis involved. Therefore, one can 'throw' a whitey having used only what may be regarded as a perfectly moderate dosage. Whiteying sometimes involves vomiting and shakiness.
In the UK cannabis television documentary, Stoned in Suburbia, former international cannabis smuggler Howard Marks refers to an episode where he whiteyed after engaging in a smoking competition with some Germans on a book-promoting visit to Germany.