Hello, Thanks for your query. There are many causes of hallucinations, including: Coming down from such drugs as marijuana, LSD, cocaine (including crack), PCP, amphetamines, heroin, ketamine, and alcohol, Delirium or dementia (visual hallucinations are most common), Epilepsy that involves a part of the brain called the temporal lobe, Fever , especially in children and the elderly, Psychiatric disorders, Severe illness, including liver failure, kidney failure, AIDS, and brain cancer A person who begins to hallucinate and is detached from reality should get checked by a health care professional right away. Many medical and psychiatric conditions that can cause hallucinations may quickly become emergencies. A person who begins to hallucinate may become nervous, paranoid, and frightened, and should not be left alone. I do hope that you have found something helpful and I will be glad to answer any further query. Take care