A woman told us last time that she had recurring threadworms and, because she is pregnant, was looking for a natural remedy.
Well, you came to the right place because worms seem to be our specialty. Loads of suggestions, such as the homeopathic remedy Cina, while another quotes us (or a What Doctors Don't Tell You back issue, to be precise) and suggests a diet high in olive oil as it prevents the worm from getting a hold.
Alternatively, try neem, myrrh and guggul, or try an Ayurvedic herbal supplier for an infusion. Metagenics produces a product called Microbicin, which contains some of the above. The homeopathic remedy Borax 30 has been recommended to one reader.