A cat's gastrointestinal discomfort caused by a sudden change of food will lead to diarrhea. If the cat's gastrointestinal tract is relatively fragile, it will also suffer from diarrhea. Diarrhea after a cat changes food usually lasts for two to three days. Severe symptoms may last longer. At this time, the amount of new food should be reduced, and an appropriate amount of probiotics should be fed to help the cat regulate its gastrointestinal tract. When changing the cat's food, follow the instructions Gradually increase the proportion of new food so that the cat can slowly adapt.