"Ecstasy is usually taken orally in pill, tablet or capsule form. Taking more than one at a time is called “bumping.”
Ecstasy is a synthetic (man-made) drug made in a laboratory. Makers may add anything they choose to the drug, such as caffeine, amphetamine1 and even cocaine. Ecstasy is illegal and has effects similar to hallucinogens and stimulants. The pills are of different colors and are sometimes marked with cartoon-like images. Mixing Ecstasy with alcohol is extremely dangerous and can be lethal.
The stimulative effects of drugs such as Ecstasy enable the user to dance for long periods, and when combined with the hot, crowded conditions found at raves, can lead to extreme dehydration and heart or kidney failure."
(Source http://www.drugfreeworld.org/drugfacts/drugs/ecstasy.html )
Not a scientific explenation but it approved some of my comment!