Ketamine is used as an anaesthetic and in third-line pain management. Furthermore, recreational use of the drug is becoming increasingly popular due to its dissociative and hallucinogenic effects. Ketamine can affect the urothelium, possibly with long-term damage to the bladder and kidneys. An otherwise healthy, 22-year-old female smoker was referred to our clinic. Shortly after starting recreational ketamine she experienced gross haematuria, urgency, frequency and dysuria. There had been no febrile episodes or flank pain. Her urine cultures were sterile. Physical examination, blood tests, urinary cytology and abdominal ultrasound results were normal. A severely inflamed bladder was seen during cystoscopy. Biopsies showed denuded urothelium and inflammation of the submucosa without malignancy. The precise mechanism of ketamine-associated urological symptoms is currently unknown. Treatment, therefore, is symptom-targeted and cessation of ketamine is imperative. We recommend that ketamine use is considered in patients with otherwise unexplained urological symptoms.