This is a particularly unpleasant effect of lactose intolerance. In short, you can find that your stool becomes very watery and perhaps loose. This can be a dangerous combination when you have gas as well, as you may lack confidence that you aren’t going to pass more than just wind! Again, this is the body rejecting the unwanted by-products caused by unbroken-down lactose. The result is a watery and highly unpleasant urgency and needs to go to the toilet.
Eating more fiber can help to alleviate these symptoms to some degree by providing bulk and sustenance to the stool.