Cannabinoid hyperemesis syndrome (CHS) is a condition characterized by cyclical vomiting without other identifiable cause in patients with chronic cannabis use. Patients with CHS report that compulsive bathing and hot showers are the only reliable treatments to improve symptoms. Cannabinoid hyperemesis syndrome is usually unresponsive to conventional pharmacologic antiemetics, and patients often require hospital admission. We report a case of CHS that improved significantly after treatment with haloperidol in the emergency department.