Dronabinol is a man-made form of cannabis (marijuana is an herbal form of cannabis). Dronabinol causes many effects on your central nervous system. Dronabinol is used to treat loss of appetite in people with AIDS. It is also used to treat severe nausea and vomiting that is caused by cancer chemotherapy. Dronabinol is for use only when other medications have been unable to control the nausea and vomiting.