A four year old child has never been dewormed, if there are worms in the body then deworming treatment is needed, otherwise it is not. Common parasites in children’s bodies are pinworms and roundworms. Pinworms have the characteristic of crawling out of the anus at night to lay eggs, and the child will have itching around the anus or perineum at night. Moreover, the body of the worms or the eggs can be excreted with the stool, so you can tell whether the child has pinworm infection through the stool. Ascaris infections do not have obvious characteristics like pinworms, so we should carefully observe the child’s performance, such as long-term pain around the umbilicus, anorexia, lethargy, and worm spots on the face, etc., to consider the existence of roundworm infection. Parents need to pay attention to the child’s daily status and changes, if there are the above symptoms, suspected parasitic infection, need to consult the doctor to clarify the diagnosis, and follow the doctor’s instructions to carry out targeted deworming treatment. If there is no parasitic infection, deworming treatment is not necessary.