Vomiting or diarrhoea are both potentially very serious, primarily from the point of view of dehydration. If your pet is vomiting or has diarrhoea, remove access to food for 24 hours (Unless your pet is a puppy or kitten). Water must, of course, always be available. The smaller the animal, the more closely you need to watch them. At the first sign of depression or marked listlessness, contact your veterinarian immediately.
If the vomiting and/or diarrhoea abates within 24 hours, start by feeding small meals of bland foods such as boiled chicken and rice. Do not feed fatty foods. After 24 hours, if all is still well, you can go resume their regular diet, gradually stepping up to full size meals.
I feed my dog a regular supermarket brand but lately his stomach is runny?
“Runny stomachs” or diarrhoea can be caused by many factors including the diet, bacterial infections or worm infestations etc. From your description it sounds like this has been going on for a while and that it is low grade. It may be that your dog had eaten something that was “off” and this has caused a low level enteritis (or inflammation of the intestine).
Take your dog off the bought food and feed small amounts of boiled chicken and rice for two days. If the diarrhoea persists (or becomes worse) see your veterinarian. If the runny stomach stops, introduce the same food. If the diarrhoea reappears, you have your answer!