Two hundred and twenty nine children aged 6 to 15 years attending the asthma clinic at the Royal Hospital for Sick Children, Edinburgh, had throat swabs taken to determine the incidence of candida colonisation of the oropharynx. One hundred children (group A), who were not receiving steroids, were compared with 91 children (group B) receiving less than 500 micrograms of inhaled beclomethasone a day and 38 children (group C) receiving 500 micrograms or more of inhaled beclomethasone a day. Sore throat and hoarse voice were not related to the presence of candida or to treatment with inhaled steroids. The incidence of candida was greater in the groups given treatment with steroids but did not increase at a higher dosage, nor was it related to the type of inhaler used. There was only one case of clinical thrush in all the children studied.