What is the origin of the idiom "chill pill" and when to use it?

The origin of the phrase "chill pill" can be traced back to the counterculture and slang of the 1960s and 1970s. During this time, there was a rise in the use of recreational drugs, including those believed to have a calming or sedative effect. It is often employed in interpersonal interactions, such as during arguments, conflicts, or moments of tension, when one person perceives another as being overly worked up or agitated. The phrase can be used humorously or playfully to gently suggest that the person should take a step back, regain composure, and approach the situation with a more relaxed mindset.