The proteolytic enzyme papain is known to cause allergic sensitization. At a research laboratory several employees developed allergic symptoms after occupational exposure to papain dust and were referred to the local Clinic of Occupational Medicine. 10 out of 22 employees reported work-related ocular itching and symptoms of rhinitis. A Histamine Release Test showed that three employees were sensitized to papain. After the introduction of more stringent hygienic procedures including the use of a fume cupboard and external washing of test tubes during use, all work-related symptoms disappeared.