Ascaris lumbricoides does not usually crawl into the human head, roundworm is the short form of worm-like roundworm nematode, is the largest nematode parasitized in the human intestinal tract, which can cause ascariasis, and it mainly consists of two stages, larval and adult, in the human body. 1. Larval stage: After entering the human body through the digestive tract, Ascaris lumbricoides eggs can hatch out larvae in the small intestine. The larvae will pass through the intestinal wall and reach the liver, heart and lungs through the blood or lymphatic system. After a period of development in the lungs, the larvae pass through the airways into the throat and are then re-swallowed into the small intestine. 2. Adult stage: After the larvae return to the intestine, they can gradually develop and mature into adult worms. Adult worms live in the intestines and feed on the semi-digested food in the intestinal lumen and continue to reproduce and lay eggs. Eggs are excreted in the feces and may be accidentally ingested again and cause infection when they develop and mature under suitable environmental conditions. When Ascariasis is found, patients should go to regular hospitals for examination and treatment under the guidance of doctors to avoid delaying the condition.