In many cases, the best initial approach is to withhold food for 12-24 hours. This gives your dog's stomach a chance to settle and recover. Make sure they have access to water during this time to prevent dehydration.
After the fasting period, you can gradually reintroduce a bland diet to your dog. This typically consists of boiled white rice and boiled chicken (without skin or bones) in a 1:1 ratio. Feed this in small, frequent meals over the course of a few days.
Canned pureed pumpkin (not pumpkin pie filling) can help with diarrhea and mild constipation. It's high in fiber and can soothe the stomach.
Plain, unsweetened yogurt with live probiotic cultures can be beneficial for a dog's upset stomach. It helps restore healthy gut bacteria.
Like rice, boiled sweet potatoes can be easy on the stomach and provide some nutrition. Mash them before feeding.
A small amount of fresh ginger can help alleviate nausea in dogs. Grate a small piece and mix it with your dog's food, or offer it as a treat.
Consult your veterinarian before giving your dog any over-the-counter medications, such as Pepto-Bismol or Imodium. These should only be administered under veterinary guidance and in the appropriate dosage.
Ensure your dog has access to fresh, clean water at all times. Dehydration can worsen an upset stomach, so encourage your dog to drink.