Papaya Leaf (Carica papaya) In modern times, we have discovered that the unripe papaya contains, in its milky juice, a protein-digesting enzyme known as papain, which resembles the animal enzyme pepsin, in its digestive action. The unusual quality of papain, unlike other enzymes that can only digest protein in an acid or an alkaline medium, is that it acts in all three, neutral, alkaline or acid. Central American Indians also used the juice of the plant to remove warts, tumors and corns. Papaya is also known to have another important quality in that it helps to prevent ulcers and helps to heal them after they have developed. It has shown the ability to increase the blood’s coagulation properties and at the same time, reduce acid secretions, which could account for the beneficial action it has on stomach ulcers.