Ice is a strong stimulant, a highly purified form of methamphetamine that can be and usually is smoked. It causes a person to be energetic, artificially confident and euphoric. The ice user will normally stay up for days if the supply of ice holds out, eating little or no food. The high from ice can last a short time like a half an hour or as long as a full day. In most cases, the high from ice methamphetamine lasts much longer than the high from cocaine.