Ascaris lumbricoides are among the medically important worms belonging to t
he phylum Nematoda (roundworms) that are parasites of the human gastrointes
tinal tract. Despite current sanitation and hygiene standards in the United
States, infection due to intestinal roundworms is not uncommon in children
and adults. A high index of suspicion is warranted as patients may present
anywhere along a spectrum of illness from asymptomatic to acutely ill. The
following is a case presentation and discussion of Ascaris lumbricoides, t
he common roundworm or intestinal longworm.