We examine patients seeking for spa treatment about erythrocyte sedimentation rate, Takata's reaction, blood picture, gastric juice, urinalysis and so on on their admittion and then repeat these tests once weekly to investigate the reaction of bathing in radioactive hot spring. A 65-year-old patient showed achylia gastrica every time in the test, but he complained no gastric symptom. On x-ray examination we found gastric polyp and verified this on operation.