There are generally no obvious side effects after deworming dogs. The topical medicine usually takes effect within 2 hours. You will see some parasite corpses appear in the dog's fur, or fall off on the carpet and sofa. Taking the medicine internally will take effect in 30 minutes. You can see dead parasites in the feces excreted by the dog. However, if the dog has a sensitive gastrointestinal tract, it may also experience slight vomiting or soft stool. , but usually it will be normal in 1-2 days. If the dog has serious abnormalities, it is not ruled out that the anthelmintic drug licked on the body surface has caused poisoning, and timely medical treatment is required.