Cocaine is a stimulant that causes a feeling of exhilaration and decreases appetite. Users may experience indifference to pain and tiredness. When it is snorted, its effects wear off within 15 minutes to half an hour so it has to be taken every 20 minutes to maintain its effect. Many users believe they perform better on cocaine, but research shows that this is probably just their perception rather than reality.

Cocaine can make the heart beat irregularly and increases body temperature. Large or frequent doses can reduce libido and lead to restlessness and paranoia. Very large doses can cause death through heart or respiratory failure. Common side effects after coming down from the drug include depression and tiredness. Withdrawal symptoms include restlessness and severe anxiety.

Some people are very sensitive to the drug and may die after their first dose. Regular snorting of the drug can cause damage to the membranes of the nose and injecting the drug through dirty or shared needles carries the risk of infection. Cocaine use during pregnancy can lead to birth defects and low birthweight babies and babies may be born addicted to the drug.

People who smoke crack cocaine are more likely to become dependent and to suffer from side effects.