Why do humans vomit worms?

Humans may vomit worms due to a parasitic infection, such as those caused by intestinal worms like roundworms or tapeworms. These parasites can inhabit the digestive system, leading to gastrointestinal distress, nausea, and vomiting as the body attempts to expel the parasites. In severe cases, a large infestation can cause the worms to be expelled from the stomach through vomiting. Proper medical treatment is necessary to address the underlying infection and eliminate the parasites.