A defoliant weed killer used in Central America and in some low-grade farming in the US. It is a dangerous chemical, and most cases of paraquat poisoning involve smoking weed that is contaminated with it. If yours is, you'll know it right away -- from what I hear, smoking newspaper is more pleasant than smoking paraquat. Some people wind up needing urgent medical care. Lung damage, etc...get your stash from British Columbia and save yourself the risk.