To date, no evidence exists in the literature as to the effects of inhaled corticosteroids (ICs) on salivary composition in patients with bronchial asthma. The aim of this study was to assess the effect of ICs on salival composition. Adult patients attending an outpatient respiratory clinic who were classified into two groups (controls and patients with bronchial asthma receiving ICs), were recruited in this cross-sectional study. For each participant, data of clinical records, baseline history of asthma, and regular IC dose were recorded. A sample of stimulated saliva was collected and processed for investigation of mucin 5B (MUC5B), lipoxygenase (LPO), total antioxidant capacity, and 8-hydroxydeoxyguanosine (8-OHdG) levels. Overall, 103 patients (49 controls and 54 patients receiving regular treatment with ICs) were recruited. No differences in comorbidities or smoking habits were observed. Patients treated with high-doses of ICs showed lower levels of salival MUC5B compared with those treated with medium IC doses or those not treated with ICs (1.60 vs. 2.20 vs. 2.53 ng/mL; p = 0.042). In patients with asthma, treatment with high-doses of ICs is associated with reduced levels of salivary MUC5B. This effect can explain some of the effects of ICs on oral health.