The term “drink the Kool-Aid” is used to describe blind acceptance of something, whether it be a high stress work environment, an order from a superior, or membership in a particular group. This term is commonly used in American politics and corporate culture, typically by outside commentators, who might say that someone is “drinking the Kool-Aid.” People will also tell each other not to drink the Kool-Aid, in the hopes of encouraging people to open their eyes to a situation before it is too late.
There are two different explanations for the origin of this phrase. Some people argue that it is a reference to the Kool-Aid Acid Tests administered by Ken Kesey and the Merry Pranksters in the 1960s. These tests were framed as challenges to the followers of the Merry Pranksters, and they involved drinking Kool-Aid that had been laced with LSD, informally known as acid.
It has also been suggested that the phrase may have its origins in the infamous Jonestown murder-suicide which occurred in 1978. During this horrific event, hundreds of people in a cult called the People's Temple died by drinking poison-laced drinks or being forced to consume poison. According to popular mythology, the poison was mixed with Kool-Aid. In fact, as ample evidence from the period indicates, the Jonestown suicides actually drank Flavor Aid, a slightly different drink.
Both explanations for the origins of "drink the Kool-Aid" involve a certain amount of faith and trust in a leader, and they also suggest a certain amount of recklessness. In the case of the Merry Pranksters, people who drank the Kool-Aid did so in the knowledge that it was laced with a psychedelic substance, while the Jonestown victims willingly drank poison, well aware that it would be deadly. Because of the association with the terrible events of Jonestown, some people find the term to be in poor taste.
Whether or not people find the term offensive, many people do agree that blind acceptance of something is generally not advised. When someone is told not to drink the Kool-Aid, the speaker is usually suggesting that the person engage in some critical thinking, and perhaps reconsider a course of action. This is especially important in the field of politics, where it can be easy to be blinded to reality by rhetoric, and it may be tempting to fall in line with a candidate or way of thinking on the basis of surface information.