Artificial sweetener is my guess for relief. It's not absorbed by bowels i've heard.
I've also heard success stories of study chewing sugar-free gum after birth which, worked better then women that didn't try it.

I've been taking 2-3 Senna tablets (CVS brand) nightly for 26yrs.
Put my 88yr ol friend on them last year. He's happy now.
Senna "Plus" has softener in it which I don't use, but have.

Emergency evac recipe is fresh spinich cooked down in frying pan with olive oil, salt, pepper & lots of garlic. Look out next day.