Cannabis, commonly known as marijuana and by numerous other names, is a preparation of the cannabis plant intended for use as a psychoactive drug and as medicine. Pharmacologically, the principal psychoactive constituent of cannabis is tetrahydrocannabinol (THC); it is one of 483 known compounds in the plant. Cannabis is often consumed for its psychoactive and physiological effects, which can include heightened mood or euphoria, relaxation, and an increase in appetite. Unwanted side-effects can sometimes include a decrease in short-term memory, dry mouth, impaired motor skills, reddening of the eyes, and feelings of paranoia or anxiety.