Straight edge is a subculture of hardcore punk whose adherents refrain from using alcohol, tobacco, and other recreational drugs in reaction to the punk subculture's perceived excesses. Some adherents refrain from engaging in promiscuous or casual sex, follow a vegetarian or vegan diet and do not consume caffeine or prescription drugs. The term "straight edge" was adopted from the 1981 song "Straight Edge" by the hardcore punk band Minor Threat.