Introduction: Complementary and alternative medicines (CAM) may be defined as treatments that fall outside of conventional healthcare. Patients with IBD often turn to CAM, mainly without discussing it with their physician. We repetitively collect information on patient-reported CAM use between 2007 and 2016. Aims and Methods: 1) to assess main categories of patient-reported CAM used by year, 2) to assess factors associated with CAM use in 2016. The Swiss IBD cohort started in November 2006. At enrollment and on a yearly basis, patients were asked to complete self-reported questionnaires. CAM were collected using a list of previously identified CAM1,2 and a free text option. Additional clinical and patient-reported data collected within the framework of the cohort was used to characterize CAM users. For descriptive purposes, we classified CAM using recommendations of the US National Center for Complementary and Integrative Health (NCCIH). Changes in life habits (e.g. diet and sportive activities) was taken as an additional category. Dietary and nutritional supplements were not assessed here. Multivariate logistic regressions were performed to search for factors associated with CAM use (i.e. 4=1 CAM reported from 2007-2016). Results: 3334 patients were included since Nov 2006. Overall, CAM were used by 21.7% to 29.3% of patients over years. Types of CAM were natural products and biologically based therapies (range: 6.9% to 11.9%), change in life habits (6.2% to 11.2%), whole medical systems and traditional medicines (5.8% to 9.6%), mind-body interventions (3.2% to 7.7%), body-based interventions (3.5% to 6.9%) and energy therapies (1.9% to 4.6%). When looking to the history of CAM use by patients in 2016, we found that 41.9%/44.4% of CD/UC patients used <=1 CAM. The most frequent CAM used by CD/UC patients were ''change in life habits'' (20.6%/18.7%), homeopathy (12.5%/14.5%) and acupuncture (9.2%/10.5%). No significant differences were observed regarding CAM use and type of diseases, except for bio-electromagnetic therapies (3.5% for UC, 1.9% for CD; p=0.010). CAM use in CD was significantly higher among women (OR=1.9; p<0.001), French-speakers (OR=1.5; p=0.002) and patients with arthritis complications (OR=1.5; p=0.001) and lower among smokers, higher SF-36 mental scores, higher age at diagnostic and B1p disease behavior profiles. CAM use in UC was significantly higher among women (OR=2.3; p<0.001), patients with arthritis complications (OR=1.4; p=0.017) and aged 36 to 45, and lower with increased IBD QoL score. Conclusion: CAM were assessed through patients self-report over time. CAM use varied between a fifth and a fourth of IBD patients during 10 years of data collection, without many changes among types of CAM. On average, 43% of patients reported a history of CAM use in 2016. Factors associated with CAM use differed between UC and CD. Some of them seemed to be linked to relieving articular and musculoskeletal pain or improving IBD-specific or mental QoL.