Cocaine stimulates the central nervous system. Its immediate effects include dilated pupils and elevated blood pressure, heart rate, respiratory rate, and body temperature. Occasional use can cause a stuffy or runny nose, while chronic use can ulcerate the mucous membrane of the nose. Injecting cocaine with contaminated equipment can cause AIDS, hepatitis, and other diseases. Preparation of free base, which involves the use of volatile solvents, can result in death or injury from fire or explosion.

Crack or freebase rock is extremely addictive, and its effects are felt within 10 seconds. The physical effects include dilated pupils, increased pulse rate, elevated blood pressure, insomnia, loss of appetite, tactile hallucinations, paranoia, and seizures. The use of cocaine can cause death by cardiac arrest or respiratory failure.