Cysteine proteinases from the fruit and latex of plants, including papaya, pineapple and fig, were previously shown to have a rapid detrimental effect, in vitro, against the rodent gastrointestinal nematodes, Heligmosomoides polygyrus (which is found in the anterior small intestine) and Trichuris muris (which resides in the caecum). Proteinases in the crude latex of papaya also showed anthelmin...