Some cats do badly on ordinary food and their owners end up trying bag after bag. Sensible is the recipe in Royal Canin's Regular range for cats with a sensitive stomach. We stock the 2 kg bag.
Feeding
Go slowly with a cat like this. Take ten days or so over the change if you need to: a small amount of the new food mixed in at first, a bit more every couple of days. Stick to the daily amount shown on the bag, and avoid adding treats or scraps while you are working out if the food suits your cat. Fresh water should be down all day.
Good to know
A change of food will not fix every upset stomach. Ongoing vomiting, loose stools or weight loss need a vet, and they may point you to one of the veterinary diets instead.
Keep the bag sealed in a cool, dry cupboard. The rest of our dry cat food is listed by brand, and there is more Royal Canin food to compare.