UNLABELLED: Previous studies have suggested an increasing use of complementary and alternative medicine (CAM) in patients with inflammatory bowel disease (IBD). Furthermore, a significant number of IBD patients fail to comply with treatment. The aim of our study was to evaluate the prevalence of non-adherence the use of CAM in Hungarian patients with IBD. METHODS: A total of 655 consecutive IBD patients (Crohn's disease [CD]: 344, age: 38.2 + or - 12.9 years; ulcerative colitis [UC]: 311, age: 44.9 + or - 15.3 years) were interviewed during the visit at specialists by self-administered questionnaire including demographic and disease-related data, as well as items analyzing the extent of non-adherence and CAM use. Patients taking more then 80% of each prescribed medicine were classified as adherent. RESULTS: The overall rate of self reported non-adherence (CD: 20.9%, UC: 20.6%) and CAM (CD: 31.7%, UC: 30.9%) use was not different between CD and UC. The most common causes of non-adherence were: forgetfulness (47.8%), too many/unnecessary pills (39.7%), being afraid of side effects (27.9%) and too frequent dosing. Most common forms of CAM were herbal tee (47.3%), homeopathy (14.6%), special diet (12.2%), and acupuncture (5.8%). In CD, disease duration, date of last follow-up visit, educational level and previous surgeries were predicting factors for non-adherence. Alternative medicine use was associated in both diseases with younger age, higher educational level and immunosuppressant use. In addition, CAM use in UC was more common in females and in patients with supportive psychiatric/psychological therapy. CONCLUSIONS: Non-adherence and CAM use is common in patients with IBD. Special attention should be paid to explore the identified predictive factors during follow-up visits to improve adherence to therapy and improving patient-doctor relationship.