There are many trials, journal reports etc of it healing peri-anal fistulas, and it has many, many studies of it lowering inflammation. I live in Canada and did HBOT in Vancouver, BC, but the Dr. I have been consulting with is in California (and one in New Orleans). They have said that HBOT will lower the inflammation but may or may not control the symptoms (nausea, diarrhea etc) of Crohn's, he has also said that he has sold many chambers to Crohn's patients to help with maintaining remission. We all know what a frustrating disease Crohn's can be, what works for one may not work for another.