Toxicity Profile for Papain (1988)

Abstract

Asthma and a variety of other allergic symptoms affecting the skin, eyes, nose and gastro-intestinal tract have occurred in people exposed to papain. There has also been some evidence of a direct irritant effect on human skin and eyes. Two fatalities followed the use of a papain solution to remove impacted meat from the gullet. Other effects of acute oral administration have included changes in blood clotting ability in humans, and diarrhoea and intestinal bleeding in mice. Emphysema (persistent damage to the lung alveoli) has been produced in laboratory animals by the inhalation of papain in aerosol form or its direct instillation into the windpipe. Foetal malformations and deaths occurred when pregnant rats and rabbits were given crude papain orally or by intraperitoneal injection, and in a very limited study in which rabbits were given the purified material by the same routes. No malformations or foetotoxic effects were evident in better-designed studies in which rats and mice were treated orally with purified papain at high dose levels. In a limited test involving repeated injection into the peritoneal cavity of rats, crude papain alone did not induce liver tumours, but it slightly accelerated the appearance of tumours induced by feeding an established liver carcinogen.