Dasatinib is a common treatment for chronic myeloid leukaemia with numerous side effects including gastrointestinal. We report a woman in her 50s who presented with haematochezia, weight loss and a positive faecal occult blood test. She was being treated for chronic myeloid leukaemia with dasatinib without the use of any concurrent medications, including non-steroidal anti-inflammatory drugs. Initial colonoscopy demonstrated moderate patchy left-sided inflammation, with biopsies revealing mild chronic inflammation and prominent eosinophilia. Dasatinib was subsequently ceased, and a repeat colonoscopy 3 months later demonstrated completely resolved inflammation both endoscopically and histologically.