Adult cats typically defecate twice a day, once in the morning and once in the evening. If your cat hasn't defecated for two days, you should consider the following:
1. Cats experience stress reactions. Unfamiliar smells in the home, the arrival of new family members, a change of environment for the cat, or sudden fright can all cause stress reactions in cats, leading to temporary physiological dysfunction and constipation for several days.
2. Poor digestion in cats. Excessive food buildup in a cat's digestive system, coupled with lack of water and exercise, can easily lead to constipation. This may be caused by eating too many different types of food or being too full. In this case, the cat should be fasted for half a day or a day, during which time it can only drink water. On the second day, reduce its food intake by half, feeding it liquid or soft food, and increase its fiber intake and exercise to see if it can defecate. If not, you can administer digestive aids as prescribed by a veterinarian, which can be given with yogurt or honey water.
3. Hairballs in cats can cause intestinal blockage. Cats often lick their fur, ingesting hair. Excessive hair buildup can block the intestines, preventing defecation. It's recommended to feed the cat cat grass and hairball remedy, or supplement with hairball-resistant cat food. If the cat still cannot defecate, a glycerin suppository can be used to stimulate bowel movements. If the cat's symptoms are severe, it's advisable to take it to the vet immediately.
4. The cat's eating habits. Owners need to consider whether the cat has been eating in the past few days. If the cat hasn't eaten or has been eating very little, it may not defecate. It is recommended that owners determine the reason why the cat is not eating.
5. Is your cat constipated? If your cat is eating but not defecating, it may be constipated. You should take your cat to a veterinary clinic for a physical examination and X-ray. For mild constipation, you can give your cat some honey water to lubricate its intestines and help it defecate. If the constipation is severe, you will need to use a glycerin suppository or enema. Usually, the cat will defecate on its own after one treatment. 
What to do if your cat is constipated:
1. Encourage your cat to exercise more. Letting your cat run around promotes intestinal peristalsis and helps with bowel movements.
2. Check your cat's stool. If your cat stays in the litter box and refuses to come out, it could be due to constipation or diarrhea. If it has diarrhea, the cat will sit in the litter box for a long time, but may only pass a small amount of stool, which can mislead the owner into thinking it's constipation. A healthy cat defecates about once a day. A cat's stool is firm and formed. In many cases, what appears to be constipation is actually a sign of another illness, and the initial symptoms are often similar. Owners need to carefully observe their cats to ensure there are no other underlying diseases.
3. Feed wet food. If constipation is caused by dry cat food, try feeding some wet food, such as canned food, to increase the moisture in the intestines.
4. Schedule a veterinary appointment. If you find your cat staying in the litter box and refusing to come out, or if you suspect your cat may be constipated, you can take your cat to the vet for a checkup. The vet can determine if your cat needs medication or dietary changes, such as switching to high-fiber cat food.
5. Encourage your cat to drink water more often. If your cat doesn't like to drink water, you can add some of its favorite flavor or honey to its water bowl, or force-feed it a little water with a push tube. If possible, buy an automatic water fountain, as cats prefer to drink running water.
If your cat is constipated, you should take it to a veterinarian as soon as possible and not delay. Inability to defecate may not be a sudden occurrence, but rather a sign of other serious illnesses. Difficulty defecating can lead to many health problems in cats, such as colonic obstruction and megacolon (colon dilatation).
