The effects of inhalation and percutaneous exposure to disodium- hexachloroplatinate (16923583) (HCP) on dermal and bronchial hypersensitivity were studied in monkeys. Biweekly for 12 weeks, monkeys were exposed to nose only inhalation of 0.2 or 2.0 milligrams per cubic meter (mg/m3) HCP aerosol for 4 hours, were exposed percutaneously to 1 milliliter (ml) of 20mg/ml HCP, or were untreated. Before and after the exposure regimens, cutaneous reactions were assessed after intradermal injections of HCP at 0.2 to 1000 micrograms/ml. Two weeks after final exposure, bronchial provocation challenges were performed for 1 minute each with saline and five HCP solutions from 0.1 to 62.5mg/ml, and pulmonary function parameters were assessed. Preexposure and postexposure dermal sensitivities did not differ for any animal. There were no significant differences in pulmonary function among groups after saline bronchial provocation. After challenge with 62.5mg/ml HCP, control values were decreased 10 to 47 percent from post saline control values for forced vital capacity (FVC), peak expiratory flow rate, forced expiratory volume (FEV) in 0.5 second to FVC ratio, and forced expiratory flows at 50, 25, and 10 percent of VC to FVC ratios; average pulmonary flow resistance (PFR) was increased 347 percent. Treated group values generally did not differ from control values, except for a 957 percent increase in PFR and a 31 percent decrease in FEV/FVC in the 0.2mg/m3 inhalation group. The authors conclude that intradermal sensitivity to HCP is not related to previous exposure. Bronchial sensitivity may also be seen in previously unexposed test animals, probably due to a pharmacologic or irritant mediated bronchoconstriction mechanism.