Ascaris lumbricoides is usually caused by bad habits, frequent contact with animals and dietary factors. 1. Bad habits: not washing hands before and after meals, not washing fresh fruits and vegetables before eating them, drinking raw water directly and other bad habits can easily lead to roundworm eggs entering the human body through the digestive system, resulting in the growth of roundworms. 2. Frequent contact with animals: frequent contact with kittens, puppies and other animals, and these animals often have roundworm eggs, also easy to cause long roundworms. 3. Dietary factors: after consuming food stained with roundworm eggs, the eggs enter the human body and continue to grow and develop, resulting in the appearance of long roundworms. The phenomenon of long roundworm, need to go to the regular hospital in time for examination and treatment. At the same time, usually need to pay attention to develop good habits, pay attention to diet and personal hygiene.