Dog diarrhea can be treated by taking away food and water for 24 hours and then serving a bland diet. However, if the dog seems dehydrated, do not take away water completely, instead give small amounts throughout the day.
The bland diet must not contain flavoring, liquid, grease or oil. Serve cooked white rice, boiled chicken without skin, boiled egg, boiled or baked potato, cottage cheese or scrambled eggs. Continue this diet until the dog passes a formed stool. Once he does, slowly increase regular dry food throughout the week, says The Fun Times Guide to Dogs.
It is not recommended to administer over-the-counter medication without the consent of a veterinarian. If the diarrhea is not getting any better, take the dog to the veterinarian immediately.