Ecstasy is a synthetic drug with both psychedelic and stimulant effects. It is a derivative of amphetamine, which is a powerful stimulant of the central nervous system. Ecstasy can come in tablet or capsule form and in different shapes and sizes. However, no matter what the size or shape, each tablet has one of a large number of signs stamped upon it. Ecstasy gives the user an immediate feeling of wellbeing, happiness, and contentment, and an extremely high surge of energy. However, within 4 to 6 hours the user may become confused or depressed, anxious, or display symptoms of paranoia. Adverse physical effects include muscle tension, involuntary teeth clenching, nausea, blurred vision, feeling faint, tremors, rapid eye movement, and sweating or chills. Because the drug allows a user to dance for long periods of time in the hot, crowded atmosphere of raves or other parties, he or she may develop dehydration, hypothermia, and heart or kidney failure. There is also a possibility of long term injury to the parts of the brain critical to thought and memory. The article describes tests to determine whether a person has used Ecstasy, including urinalysis, sweat patches and hair and saliva analysis. It also describes tests to identify the contents of unknown tablets.