This chapter discusses cocaine use and its various medical conditions. Cocaine is a colorless, odorless, crystalline substance with bitter taste and slightly soluble in water, but freely soluble in alcohol. It is an alkaloid deliriant, obtained from dried leaves of erythroxylum coca. Cocaine is rapidly absorbed from the mucous membranes and subcutaneous tissues. Its signs and Symptoms include stage of excitement and stage of depression. After an hour of its use, respiration becomes slow, there is profuse sweating, and patient becomes calm and dull. For treatment in such cases, Intensive supportive therapy is needed in case of acute intoxication and Airways are kept clean, artificial respiration and oxygen inhalation as required. Signs and symptoms of cocainism include emaciation, anorexia, digestive disturbances, face is pale, and degeneration of CNS with hallucinations, convulsions and delirium may occur. Magnan\'s syndrome/cocaine bug, seen in cocaine addicts, is a type of tactile hallucination.