The time of fasting and water deprivation for gastroenteritis in dogs varies with the condition. Generally speaking, dogs with gastroenteritis are deprived of water for 6- 12 hours and food for 12-24 hours. This will give the dog's stomach a chance to rest and recover for a while. During fasting, make sure the dog has enough water and can give some digestive tract support drugs according to the veterinary advice. After fasting, gradually return to normal diet, and you can give digestible food, such as rice and cooked chicken. However, please note that this is only a general suggestion. The specific time of fasting and water prohibition needs to be determined according to the age, weight, illness and veterinary guidance of dogs and dogs.