Answer:
If the laxative in not in bulk amount then there can be a problem of diverticulosis because with a small amount of residue in intestine the contraction of muscles starts which is not good.
Secondly, the laxative should not cause irritation in the intestinal mucosa else diarrhea will occur.
The contents of intestine will move very fastly through intestines and leaves very less time for absorption of water, which results in the electrolyte imbalance and dehydration.