What is the reason why a dog’s stool is normal at first and then loose?

Pet     9:02am, 11 October 2025

Nowadays, more and more people are raising dogs. To see whether the dogs are healthy, the main thing is to see whether their stools are normal. Some dogs will have diarrhea when they are sick, but what is the reason why dogs have normal stools first and then have diarrhea? Let’s give a brief introduction below.

A dog's stool may be normal at first and then loose, which may be caused by improper diet, indigestion, abdominal cold, parasitic infection, etc.

1. Improper diet

If the owner feeds the dog food that has gone bad, or feeds the dog raw and cold irritating food, such as ice cream, chili, etc., the dog's gastrointestinal tract will be stimulated and cause diarrhea. In this regard, it is recommended that the owner fast for half a day and then let the dog drink some water. After the dog improves, he can feed him some easily digestible food.

2. Indigestion

The digestive capacity of the dog's gastrointestinal tract is limited, especially the gastrointestinal digestive system of puppies is not fully developed. If they eat food that is difficult to digest or eat too much at one time, they may have normal stools and then loose stools. If this is the case, the owner can feed the dog an appropriate amount of probiotics and antidiarrheal drugs to stop diarrhea and regulate the intestinal tract.

3. Abdominal cold

The hair on the dog's belly is relatively sparse. If the dog sleeps on the cold floor for a long time, or does not keep warm when the temperature suddenly drops, it will easily lead to cold abdomen, abnormal defecation, and symptoms such as sneezing and runny nose. In this regard, the owner should quickly take measures to keep the dog warm and consult a pet doctor for medication.

4. Parasitic infection

If the owner has not dewormed the dog for a long time, and there is blood in the dog's diarrhea, it should be considered that the dog is infected with internal parasites. Because there are many parasites that cause diarrhea in dogs, common ones include roundworms, tapeworms, coccidia, and hookworms. The specific deworming methods are also different. Therefore, it is recommended to take the dog to the pet hospital for a microscopic fecal examination to determine what kind of parasite is causing the diarrhea, and then use deworming drugs accordingly.