Background Patients with inflammatory bowel disease are using online community forums (OCFs) to seek emotional support. The impact of OCFs on well-being and their emotional content are unknown. Methods We used an unsupervised machine learning algorithm to identify the thematic content of 51,591 public, online posts from the Crohn’s & Colitis Foundation Community Forum. Results We identified 10,702 (20.8%) posts expressing: gratitude (40%), anxiety/fear (20.8%), empathy (18.2%), anger/frustration (13.4%), hope (13.2%), happiness (10.0%), sadness/depression (5.8%), shame/guilt (2.5%), and/or loneliness (2.5%). A common subtheme was the importance of fostering social support. Conclusions High-throughput, machine learning-directed analysis of OCFs may help identify psychosocial impacts of inflammatory bowel disease on patients and their caregivers.