蛔虫病（英语：ascariasis），是一种经线虫动物门的寄生虫蛔虫所导致的疾病。超过85%的感染病例─尤其是蛔虫数目非常少的情况下─是没有症状的。随着蛔虫数目的增加，便可能会出现症状：一开始可能会有呼吸困难与发烧的情况，之后产生腹部肿胀、腹痛与腹泻。儿童是最常被感染的族群，而该疾病也会导致儿童体重无法增加、营养不良与学习问题。

蛔虫病是经由食用或饮用存有从粪便而来的蛔虫卵之食物或水而感染。常见的感染途径为生吃蔬菜、瓜果。在春夏季节，气候温暖潮湿，适于蛔虫繁殖发育，人更容易感染蛔虫病。蛔虫的卵会在肠道孵化，孵化的幼虫会穿过肠壁、经由血液而迁移到肺部。这些幼虫会侵入肺泡，往上通过气管，感染者气管受到刺激而产生咳嗽反射，将这些幼虫咳至咽喉，随后吞入这些幼虫。被吞入的幼虫会经由胃部，再次进入肠道成长为成虫。

Ascariasis is a disease caused by the parasitic roundworm Ascaris lumbricoides. Infections have no symptoms in more than 85% of cases, especially if the number of worms is small. Symptoms increase with the number of worms present and may include shortness of breath and fever in the beginning of the disease. These may be followed by symptoms of abdominal swelling, abdominal pain and diarrhea. Children are most commonly affected, and in this age group the infection may also cause poor weight gain, malnutrition and learning problems.