Ulcerative colitis is a disease of the intestine caused by the immune system over-reacting - in this disease the white blood cells attack the gut as though it's a foreign invader, making it bleed. Mother-of-two, Anna Glanz, from Iowa, suffers from it and gets terrible cramps and sudden, intense attacks of diarrhoea. The disease is incurable, but she is now taking part in an experimental trial run by Dr Joel Weinstock, a spedrug spammert in bowel disorders. He's giving her worms to try to treat the disease.