Studies were performed on 13 Polynesian children who suffered from recurrent respiratory disease characterised by cough, wheeze, tachypnoea and radiological opacities. Only one was substantially underweight. Most had iron deficiency anaemia. Serum IgG levels were high with a less definite trend to raised IgA and IgM levels. Precipitating antibodies to cow's milk protein were found in 6 out of 10 children tested who were currently on cow's milk feeds. The proportion of rosette-forming lymphocytes was reduced in 8 of the 12 tested. The Mantoux test using using 10 TU of PPD was negative in 7 out of 10 children who had had BCG in the newborn period. The likelihood of cow's milk contributing to the respiratory disease in these children is discussed.