Although helminthology, the study of parasitic worms, may have a subject that lots of people are grossed out by, it's actually an important subject for the health of humans and animals.
To be more precise, helminthology is the study of helminths, a type of worm that lives inside the body of its hosts. Many helminths live in the hosts' intestines, and the adult worms are large enough to be seen without a microscope. Different species specialize in invading different hosts, from humans to crickets. Their name comes from the Greek word helmins, meaning "worm."