April 20 is a popular day known colloquially as 4/20 — an unofficial day to celebrate marijuana. What’s the tie-in between 4/20 and pot? Some say it has to do with the Grateful Dead. Others give credit to a group of teens in 1970s who were searching for a fabled pot farm. Either way, marijuana is gaining traction as a therapeutic — 29 states and the District of Columbia have legalized its medicinal use.
How much do you know about marijuana and its medicinal properties? Take our quiz. We hope you get a high score.