CBD has very few known adverse side effects at any dose. According to research, high doses of up to 1500mg/daily of CBD seem to be well tolerated in humans.20 THC in high doses can make a person feel out of sorts for a while, but there are no known fatalities from overdosing on cannabis, as there are for many pharmaceutical drugs. CBD and other plant cannabinoids can potentially interact with many pharmaceuticals, decreasing their effectiveness by inhibiting the activity of cytochrome P450, a family of liver enzymes. This potentially affects the body’s metabolism of a wide range of compounds – up to 60% of commonly prescribed pharmaceuticals. The primary issue is that CBD is metabolized by cytochrome P450 enzymes, occupying the site of enzymatic activity and preventing it from metabolizing other compounds.