This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
A strong injection of salt into the rectum is an efficient cure for these parasites, and is best given with quassia or other bitter. Salt is also taken internally to prevent recurrence of thread or round worms, and so strong at one time was the belief in its efficacy, that an ancient law in Holland deprived certain criminals of salt in their diet, in order to allow intestinal worms to develop and devour the victims!
Leeches are very sensitive to the action of salt; it will make them disgorge blood they have swallowed, and a saline injection will dislodge them from the rectum or vagina. It is advisable to administer the same remedy freely should they by accident have passed from the nose or mouth to the stomach.