Background and Aim: : Saliva is an essential fluid for protecting the mouth, and any change in its quality or quantity affects the health of the oral cavity. Asthma and the medications used to treat it may decrease salivary flow and change salivary components, including changes in the pH of the dental plaque. The purpose of this study was to determine the salivary flow and pH in asthmatic and non-asthmatic patients referring to the Asthma Clinic of Masih Daneshvari Hospital in Tehran, Iran, in 2019. Materials and Methods: : This cross-sectional study was performed on 70 patients aged 18-60 years (35 asthmatic patients and 35 healthy controls). After completing the datasheets, saliva was collected by the spitting method for 5 minutes. Its flow rate was recorded in ml/minute, and its pH was measured by a pH meter. The results were analyzed via SPSS 20 software according to the t-test and Mann-U-Whitney statistical test. Result: The mean salivary flow rate was 4.22 ml/minute in the asthmatic group and 5.44 ml/minute in the healthy group (P<0.005). The mean salivary pH in the asthmatic patients and the control group was 6.9 and 7.1 (P<0.005), respectively, indicating that salivary flow rate and pH were significantly lower compared to the healthy group. Statistical analyses also showed that the higher the frequency of drug use, the greater the decrease in the salivary flow (P<0.005). Conclusion:It seems that asthma and the drugs used for its treatment reduce salivary flow and pH.