This spring, the Medical Marijuana Caregivers of Maine joined the usual coalition of anti-pot forces that includes active law-enforcement groups, social conservatives and public health advocates to oppose a state bill that would legalize possession of small quantities of the drug.
And it's not a good idea to use it as mouthwash. Hydrogen peroxide (in dilute form) is used as a tooth whitener (check the active ingredients on those gel-based tooth whiteners, they usually use H2O2). It also has the side effect of turning your gums pale temporarily, though it wears off in a few hours.
How is hydrogen peroxide used to whiten teeth? Teeth contain organic molecules in their enamel and the dentin. These molecules reflect light and are responsible for their coloration. The more complex these molecules, the more light they reflect and the more teeth appear stained or discoloured.