Marijuana

Marijuana, also known as cannabis, is a plant that is used as a smoking herb or ingested in food preparations that leaves its users in a mellow state of euphoria, although it can also temporarily impair their motor coordination. One of its known side effects is that it can cause its users to have a sense of paranoia. It is considered an illegal substance in most countries and is strictly prohibited for uses outside of medicine in areas that have allowed for limited and regulated legalization.

Mainstream Smurfs Media
In the cartoon show crossover "Cartoon All-Stars To The Rescue", the human character Michael is shown to be a user of marijuana, and the cartoon characters of the special attempt to show how marijuana can lead to the use of other drugs that can affect Michael's health in the future, eventually leading to Michael swearing off the use of all drugs when he sees his little sister Corey being tempted by the evil influence known as Smoke into going for his box of marijuana joints.

This substance does not appear in any other known forms of Smurfs media apart from non-canonical fan creations of an adult nature.