“The exact cause is really unclear,” says Glatter. “Some research indicates that it may be related to a genetic polymorphism in what we call the cytochrome P450 enzyme system, which is how we metabolize marijuana.” But there’s probably more to it than that. For one thing, patients suffering from CVS often compulsively bathe during vomiting episodes, perhaps because taking a hot bath or shower can reduce nausea in the short term. Glatter says it may be the case that hot showers “ameliorate the disequilibrium, and re-adjust the set point of the thermoregulatory system in the hypothalamus.” Another theory, he says, is that “heat dilates blood vessels in the skin and muscle” which in turn diverts blood flow away from the circulation system that supplies the gut and intestines. “When there is less blood flow to the gut and intestines, symptoms of nausea and vomiting are reduced,” adds Glatter.