Based on the clinical manifestations, ascariasis can be classified into syndromes of ascarides lodging in the intestine, ascarides reaching the gallbladder and ascarides caking in the intestine. Ascarides lodging in the intestine may have no symptoms, or may have intermittent pain around navel without obvious tenderness but with cord-shaped sensation when pressed; the commonly-seen symptoms of ascarides reaching the gallbladder include severe paroxysmal colic of the region below xiphoid process and the upper part of right abdomen accompanied by nausea and vomiting; the commonly-encountered symptoms of ascarides caking in the intestine are severe paroxysmal abdominal pain mainly around the navel, accompanied by frequent vomiting, possible vomiting of ascarides, indefinite abdominal cord-shaped mass which has activity when pressed.