Deanna L. asked us about blue roundhead mushrooms this week. Are they psychoactive, are they edible, and does cooking them change their effects? Stropharia caerulea is one of the few naturally blue-green mushrooms. It’s not considered the tastiest edible species and can cause unpleasant gastrointestinal symptoms. While we’re not mushroom experts on that particular patch of mycelium, S. caerulea has been shown not to contain detectable amounts of psilocybin (Kristinsson 2008). Some authorities, however, have claimed to have found psilocybin in the species, though that hasn’t been corroborated by recent research.