The delayed cutaneous hypersensitivity to seven ubiquitous antigens (Multitest CMI, Istitute Mĕrieux) was evaluated in normal healthy volunteers before and at the time of intramuscular administration of 50 (12 subjects) or 50 + 50 (nine subjects) units of salmon calcitonin or 2 ml of saline (eight subjects). The delayed cutaneous hypersensitivity, in terms of number of positive tests or sum of positive tests, significantly fell in both groups given salmon calcitonin, but no changes were observed in the control group. These results indicate that salmon calcitonin, as well as inhibiting osteoclastic bone resorption, has important immunological effects.