This is a case report of a 19-year-old woman with cannabinoid hyperemesis syndrome (CHS), which is characterised by cyclic vomiting and nausea, relieved by hot showers and caused by chronic cannabis usage. Many diagnoses must be ruled out, but the suspicion of cannabis usage must be present. Early suspicion of CHS can prevent overtreatment and unnecessary investigations. Lack of evidence makes treatment difficult and is primarily symptomatic. Attention to cannabis usage is needed when admitting patients with emesis.