Pinworms are small, milky white, two to five millimeters long in males and eight to thirteen millimeters long in females, and resemble white threads, so they are generally called threadworms. Human pinworms are parasitic only in the lower part of the human small intestine, cecum, appendix and large intestine, and are common intestinal parasites. It also causes loss of appetite, weight loss, and fingernail biting. The treatment can be oral roundworm spirit, or pinworm spirit. The actual personal hygiene is usually to pay more attention to personal hygiene, wash the anus and change the underwear regularly.