Injurious effect of Blasticidin-S, the agricultural antibiotic effective against Piricurariaorizae, discovered in Japan was investigated in the production plant. The result of this investigation was reported and discussion was made on its protective measures. Blasticidin-S, causes very severe, acute inflammation on the mucous membrane and epidermis exposed to the antibiotic. Among the injurious effects of Blasticidin-S, some marked symptoms in the eyes, intestines, and skin were described. Results of investigations on subjective symptoms of the whole workers were listed and adverse effect of Blasticidin-S against human body was clarified. Measures against these injuries include, first, the prevention of. contact with the antibiotic and then prevention of continuous exposure, when the worker is likely to be in contact with Blasticidin-S in minute amounts. These measures were found to lessen the degree of injury. Any injuries that have occurred have been alleviated by administration of antiinflammatory hormone and antibiotics. This seems tosuggest measures against future injuries.