As long as he is eating, drinking, playing and acting otherwise normal. Make sure he is not getting into anything he shouldn't be eating (one of mine had diarrhea from getting into the dog's food bowl). And make sure he's not chewing on house plants. Many are poisonous to cats but just serious enough to cause diarrhea. If it continues for more than a couple days and you're sure he's not eating anything bad, then you should call the vet. Kittens should be de-wormed and vaccinated at 8 weeks and that is usually the earliest they can be separated from their mother. The intestinal parasites that they get from their mother's milk can cause digestive issues so the de-worming may help.
Thanks for the info! He is better, his stools are firmer, I did catch him in the dog food! I also have a another cat, so keeping everyones food separated is going to be a job, but that's part of having pets! New kitten is on kitty chow, other cat on weight control, plus the dog food.
A kittens digestive tract is very sensitive. Any switching of foods will cause diarrhea. So if the kitten is getting to the adult cat food and the dogs food. That is what is causing it. Also parasites, make sure you have the kitten dewormed by a vet as soon as possible. The kitten can transmit the worms to the adult cat by sharing the same litter box. The dewormer they sell in stores is not worth a hill of beans. Also the dewormer treatment must be done on one day, and ten days later another dose. The dewormer will only kill the worms that are hatched. Within the ten days, the eggs will hatch, hence, another dose is needed. Mention to your vet that you have an adult cat at home, and I am quite sure the vet will have you give the dewormer to your adult cat as well. Hope this helps, and good luck with the kitten!!