After deworming, dogs may experience vomiting, diarrhea, loss of appetite, poor energy and other reactions. This is a normal phenomenon. You can fast the dog first, then let the dog rest and drink more water, and feed it appropriately. Some probiotics can help the dog regulate his stomach. Generally, the dog can recover on its own in two or three days. If there is no improvement in more than three days, it is best to take the dog to the pet hospital for examination and treatment to avoid aggravation of the situation.