Pulmonary involvement in the course of inflammatory bowel disease has been a subject of interest to clinicians for long time, but despite this, its epidemiology and potential pathomechanisms remain obscured. Equally unclear is the role of medications used for bowel disease treatment in lung disease development. We present three patients with ulcerative colitis, all treated with mesalazine, in whom unexplained lung disease developed. Due to different clinical and radiological presentation, different conditions were initially placed on the top of the differential list in each of them. The outcome was favourable in all patients despite differences in management. We compared our patients with similar cases from literature. We show the level of difficulty and complexity in the issue of lung disease in patients with inflammatory bowel disease.