The purpose of the present study was to investigate the effect on saliva and plaque pH of beta 2 agonist (salbutamol 400 mcg) and inhaler corticosteroid (fluticasonepropionate 250 mcg). The interproximal plaque pH responses to these medicaments and examine the effect of chewing gum after the usage of these inhalers. Thirty children of both sexes, from six to fourteen years old, participated in the study. The pH microelectrode was used in the study. The interdental sites chosen were those between the premolars in the 4 quadrants. The pH measurements were made baseline and 1, 5, 10, 20, 30 minutes after the use of medicaments as inhaler and also saliva was stimulated by sugar free chewing gum (Vivident). Data analyses were conducted using a statistical package through the University's computing center. The resulting pH values decreased in all four plaque sites and saliva during 30 minutes after inhaler drugs. After rinsing with water, the pH values also decreased (p < 0.001). Decreasing pH increased with chewing gum (p < 0.001). The hypothesis is that a decrease in pH in medicated asthmatics could be caused by inhaler drugs. Conclusive evidence for the relative role of the disease and the drug in saliva secretion and composition seems to require a longitudinal study on asthmatics before and after the onset of drug administration. We suggest that children with bronchial asthma treated with inhaler drugs should receive special preventive attention.