I have worked out an answer for you below ...
Diarrhoea in the cat is a fairly common event and most cases are not so serious, however this sort of situation is always a gamble so if you want to be 100% sure you are doing the right thing you should have a vet check him over sooner rather than later.
That said that there are a number of home remedies for diarrhoea in the cat which some owners use before getting a vet involved, these can often work well for uncomplicated cases where for example a cat has eaten something he should not have out in the yard, or had some unaccustomed rich foodstuff, or has somehow acquired a minor tummy bug of some kind.
I will give you some examples.
1. Some owners try and control the situation with diet alone before they try anything else. This is logical and often works, the basis of this is to give the intestinal tract a complete rest and then bring it back slowly to function, resting the alimentary tract is the critical factor. It would go something like this ...
A. Keep him in if he is not a house cat and starve him for 24 hours but make sure he has access to water.
B. The next day feed him four or five small light meals in the day. These meals should be the likes of chicken, fish, scrambled egg etc. with a little rice.
C. If he picks up on this diet gradually reintroduce his normal diet over the next few days.
2. Live yogurt added to the food or given orally can often help. You see some gastro-enteritis situations are caused by an imbalance in the bacteria in your dog's gut. Live yogurt is full of " good " bacteria and will seed them into your cat's intestinal tract and restore the balance. A couple of teaspoons twice a day should be fine.
Of course if any of the above does not quickly start to work or if he deteriorates further in any way you should have your vet check him over just to be on the safe side, sometimes prescription drugs are required.
I hope I have covered your question fully enough but if you would like further clarification or to talk things over a bit more then I will be on-line for the next hour or so and I will be more than pleased to continue working with you.
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