Updated December 15, 2014.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

What is sold as cocaine is usually a mixture of cocaine hydrochloride and filler ingredients that share the appearance of cocaine, some of which have psychoactive or numbing effects, and some of which are simply white powders.

Psychoactive Ingredients

Cocaine itself is the most potent known naturally occuring stimulant, containing a chemical substance called a benzoylmethylecgonine. It is found in the leaves of the Erythroxylon coca plant, which grows in Peru, Bolivia, Java and Columbia.

This stimulant is the main psychoactive ingredient in cocaine, which produces the cocaine high.

In their natural form, coca leaves can be chewed to produce a sense of elevated energy and well-being, and reduce appetite, but don't seem to cause cocaine withdrawal or addiction. Powder and freebase cocaine and crack have been artificially concentrated to produce a more rapid onset of effects, and this makes it more addictive. The cocaine leave are made into cocaine paste, actually a white, gray, or dull brown powder. This intermediate form of cocaine contains 40-80% cocaine sulfate, and is used in South America and some parts of the United States, where it is known by the names pasta or bazooka.

Powder cocaine is further refined to produce cocaine hydrochloride crystal, the key ingredient in powder cocaine and crack cocaine.

Street cocaine is unlikely to contain cocaine as the only psychoactive ingredient, as cheaper stimulants such as amphetamines, caffeine, methylphenidate, ergotamine, and aminophylline are typically mixed with cocaine.

Cocaine users are often surprised to find these other stimulants being reported on drug tests, as they believed they had only taken cocaine.

Anaesthetic Ingredients

Cocaine has a naturally numbing effect on the nose, throat, and gums, so local anaesthetics are often mixed with cocaine to give experienced users the impression that the cocaine they have purchased is of a high quality. These local anaesthetics include procaine (Novocain®), lidocaine, tetracaine, and benzocaine.

Although anaesthetics themselves are pure and legally used for medical and dental purposes, they are not without risks. There are clinical contraindications with these drugs, and they may have significant side effects. These side effects may be unsafe, and distressing to experience while under the influence of cocaine, especially because of the cocaine effects of anxiety and paranoia.

Filler Ingredients

Various inert white powders are used as fillers, including talc, flour, cornstarch, and various sugars.

Poisonous Ingredients

Although it is relatively rare for poisonous ingredients to be mixed into cocaine, the dangers are severe, so you should seek medical help immediately if you or someone else has taken cocaine and is experiencing adverse effects. Cocaine containing poison is known as a death hit.

Strychnine is a toxic ingredient, sometimes mixed with cocaine, that is used in rat poison and can cause death in humans. Psychological symptoms of strychnine poisoning are similar to the negative effects people sometimes experience from cocaine, including anxiety, restlessness, agitation and an increased startle response, and physical symptoms include muscle pain and spasms, rigidity of the arms and legs, and arching of the neck and back. Jaw tension is also a symptom shared with stimulants such as meth and ecstasy, so may be easily missed. Call 911 if these symptoms appear after using cocaine.

Arsenic is another poison sometimes found in cocaine. Arsenic can cause death if consumed in large amounts, and health problems including abnormal heart rhythm, damage to the blood vessels, reduced blood cell production, corns and warts on the hands, feet and torso, and cancer. Symptoms of arsenic exposure include vomiting, abdominal pain, and diarrhea and pins and needles in the hands and feet. Call 911 if these symptoms appear after using cocaine.

Other Ingredients

Several other ingredients have been found in cocaine, which may or may not be included in any given batch. These include, but are not limited to:

• Quinine is sometimes added to cocaine for its bitter flavor.
• Thiamin also known as vitamin B1.
• Tyramine, a food substance that can induce migraines, which is dangerous for people taking MAOI antidepressants.
• Sodium carbonate, also known as washing soda.
• Magnesium silicate, also known as asbestos.
• Magnesium sulfate, also known as epsom salts.
• Salicylamide, a non-prescription pain reliever.

Freebase and crack cocaine, which are types of cocaine that have been further refined so that they can be smoked, are prepared using alkalis, such as ammonia or sodium bicarbonate (baking soda), and/or solvents, such as ether.

<sub>Sources

Acosta, M., Haller, D., and Schnoll, S. "Cocaine and Stimulants." In R. Frances, S. Miller and A. Mack (Editors). Clinical Textbook of Addictive Disorders. 3rd edition. New York: Guilford. 2005.

ATSDR. ToxFAQs™ for Arsenic. August 2007. Retrieved 22 June 2011.

BBC News Benzocaine targeted in drugs war on cutting agents. 8 August 2010. Retrieved 22 June 2011.

CDC Case Definition: Arsenic (Inorganic). 9 March 2005. Retrieved 22 June 2011.

CDC Facts About Strychnine. 14 May 2003. Retrieved 22 June 2011.</sub>