Cannabis and marijuana are used inter changeably, but in reality they are different. cannabis is the name for all products derived from the plant cannabis sativa, the plant has about 540 chemical substances. Marijuana on the other hand is one of these products derived from the cannabis plant which contains tetrahydrocannabinol that alters mental state and causes ‘high’ But Medical cannabis are certain chemical substances from cannabis plant known as cannabinoids and are used for medical purposes. They have been approved for use in various countries. The USFDA has approved several drugs that contain individual cannabinoids for example ,Epidiolex was approved for treatment of seizure associated with Lenox-Gastaut syndrome or Dravet syndrome two rare and severe forms of Epilepsy ,Dronabiol and Nabilone are used in Nausea and vomiting caused by cancer therapy and also Dronabiol is used to treat loss of appetite ,weight loss in people with HIV/AIDS.