A 19-year old female was admitted with intractable nausea, vomiting and intermittent abdominal pain. The medical history of the patient contained nine previous, similar admissions and extensive investigations within several medical specialties at several hospitals in the vicinity of Copenhagen, as well as abroad during the patient's holidays. All of the investigations were without findings that could explain the recurring condition. The patient reported chronic morning sickness, exacerbating with vomiting and abdominal pain every month since the age of 13. Especially during these exacerbations, the patient took frequent hot baths for symptom relief. Cannabinoid hyperemesis syndrome (CHS) was suspected and the patient admitted having used cannabis daily for the past seven years. She received parenteral rehydration and counseling regarding cannabis cessation. Two months after discharge the patient was no longer using cannabis and was symptom-free. This case report intends to raise clinicians' awareness of CHS in Sweden, a country where 55 000 of the inhabitants aged 16 years and older report having used cannabis during the past 30 day period.