Sorry a little late with a reply. My husband had severe cramps and also in constant urge to evacuate — with the advice of some amazing folks here, this worked for him. Psyllium husk every morning (sometimes evening too if symptoms continues), proactively takes loperamide (Imodium) every morning up to 3 times a day on the days he’s on oral chemo, and Buscopan if he feels cramps are about to start. He finds being proactive works so he does it as part of his routine now.
There are some foods he can’t tolerate anymore, for example sashimi or large quantities of cheese or milk.