A word of caution from my experience.
Its true some can benefits from taking lactulose.
I was having really hard times when taking recommended lactulose for constipation. Means more fermentation gases more constipation more toxins more anxiety more clogged liver. Guess its depending on the status of your flora BEFORE taking it.
Indeed some good colonic bacteria can use it bur also some "bad" bacteria. I have also candida and SIBO.