I thank you for your response however this did not answer the question. If you look at the question again you will see that I am trying to get info on the duration of the Kristalose (lactolose) once ingested - not the amount of time it takes to have an effect but the length of time it is working in your system once taken.
FYI - I am taking Xifaxan (rather expensive though).
Basically you should have between 3-4 bowel movements per day, normally. More, if ammonia is causing hepatic encephalopathy (HE). You want to "keep things moving along so to speak". When food stays in you, more and more ammonia is created. It does take a few days for it to work so be patient and you will feel better soon. Remember no red meat. Chicken and fish is okay. Red meat gives off lots of ammonia during digestion.
Has he prescribed Xifaxan (rifaximin) also? It really works wonders for many of us without the side effects of lactulose and kristalose.
Take care.
Hector