In the 1950s, phencyclidine was investigated as an anesthetic but, due to the side efffects of confusion and delirium, its development for human use was discontinued. It became commercially available for use as a veterinary anesthetic in the 1960s under the trade name of Sernylan and was placed in Schedule III of the CSA. In 1978, due to considerable abuse of phencyclidine, it was transferred to Schedule II of the CSA and manufacturing of Sernylan was discontinued. Today, virtually all of the phencyclidine encountered on the illicit market in the United States is produced in clandestine laboratories.

Phencyclidine, more commonly known as PCP, is illicitly marketed under a number of other names including Angel Dust, Supergrass, Killer Weed, Embalming Fluid, and Rocket Fuel, reflecting the range of its bizarre and volatile effects. In its pure form, it is a white crystalline powder that readily dissolves in water. However, most PCP on the illicit market contains a number of contaminates as a result of makeshift manufacturing, causing the color to range from tan to brown, and the consistency from powder to a gummy mass. Although sold in tablets and capsules as well as in powder and liquid form, it is commonly applied to a leafy material, such as parsley, mint, oregano or marijuana, and smoked.

The drug's effects are as varied as its appearance. A moderate amount of PCP often causes the user to feel detached, distant and estranged from his surroundings. Numbness, slurred speech and loss of coordination may be accompanied by a sense of strength and invulnerability. A blank stare, rapid and involuntary eye movements, and an exaggerated gait are among the more observable effects. Auditory hallucinations, image distortion, severe mood disorders, and amnesia may also occur. In some users, PCP may cause acute anxiety and a feeling of impending doom, in others, paranoia and violent hostility, and in some it may produce a psychoses indistinguishable from schizophrenia. PCP use is associated with a number of risks and many believe it to be one of the most dangerous drugs of abuse.

Modification of the manufacturing process may yield chemically related ananogues capable of producing psychic effects similar to PCP. Four of these substances (N-ethyl-l-phenylcyclohexylamine or PCE, l-(phenylcyclohexyl)-pyrrolidine or PCPy, l[l-(2-thienyl)-cyclohexyl]-piperdine or TCP, and l-[l-(2-thienyl)cyclohexyl]cyclohexyl]pyrrolidine or TCPy have been encountered on the illicit market and have been placed in Schedule I of the CSA. LSD is also a Schedule I hallucinogen.