Occupational inhalation allergy (bronchial asthma, rhinitis, conjunctivitis), often in association with urticaria and Quincke oedema is common in platinum associated industry. It is due to sensitization against platinum chloride. The reaction mechanism corresponds to the immediate type (I) allergy as shown by clinical tests (skin tests), in virtro (histamine release from leucocytes) and in vivo investigations (passive cutaneous anaphylaxis in apes). The degree of sensitization is so high that test investigations in affected persons must be performed with care. For prick testing with platinum chloride (PtCl6)2- or (PtCl4)2- an initial concentration of 10(-9) g/ml is recommended. As an average of 60% of people working in the platinum industry fall ill with bronchial asthma more stringent protective occupational measures are suggested.