There are no good studies in humans that I know of to answer your question.
Inflammatory bowel diseases such as Crohn’s and Ulcerative Colitis, are immune deficiency diseases that involve chronic inflammation of the gastrointestinal tract. They can cause persistent cramping, diarrhea, obstruction, and rectal bleeding.
Patients suffering from Crohn’s disease, or from any type of irritable bowel disease, have a higher level of cannabinoid receptors in their gastrointestinal tract. The cannabinoids found in cannabis can help to reduce the inflammation caused by these conditions. In 2013, the journal Clinical Gastroenterology and Hepatology found that 10 of 11 patients in the cannabis group of a study had a significant reduction in their symptoms and 5 had complete remission with the use of cannabis.
Our body has its own cannabinoid system referred to as the endocannabinoid system and we have cannabinoid receptors, CB1 and CB2, in the digestive system. The cannabinoid system has been shown to be involved in regulating the immune system through its immunomodulatory properties. Cannabinoids suppress inflammatory response and reduce disease symptoms. This happens through multiple, complicated biochemical pathways.
A mouse study in Naples, 2008, showed that when CB1 receptors are activated, they can decrease intestinal movement and the secretion of intestinal fluids. CB2 receptor stimulation can lead to an increase in T-cell, white blood cells, and other body cells that mediate inflammation. There is also evidence that THC may be helpful in reducing the leakage of fluids through the lining of the gastrointestinal tract.
Due to stomach sensitivities in patients with Crohn’s, vaporization or smoking has seemed to be the best delivery method for medical cannabis. Edible forms, however, allow for the cannabis to directly sooth the gastrointestinal tract.
While there is no medical evidence for specific strains, dosages, etc, and while I would recommend using CBD oil as an adjunct to current therapies, I have had good results for patients using CBD Oils in a 2:1 ratio three times per day with the addition of some THC pills in extracted form in capsules for flares and to stimulate appetite and sleep.
Typical starting doses of CBD for most conditions are 2.5-5mg/day.