Generally, if you talk to your doctor about
it, they will script
something like Questran or, I think, another is Colostid.
The last 3 feet or so of the small intestine is where most of the bile salts needed for digestion are absorbed. The bile salts are irritating to the more sensitive colon. Often after resection not enough of the bile salts are absorbed before reaching the colon which irritates the colon and reduces its ability to absorb the liquid and solidify the stool - ergo diarrhea.
The Questran and its like serve to in some way reduce the bile salts and their irritating effect on the colon mucosa so that the colon can more properly do its job of absorbing the liquid and forming the stool.
My computer says I need to upgrade my brain to be compatible with its new software.