The purpose of this study was to investigate the effects of carboxymethylcellulose (CMC)-based artificial saliva according to residual secretory potency, assessed by the salivary flow rate in patients with dry mouth. Fifty patients (6 men and 44 women, 57.8+/-13.2 year of age) with a chief complaint of dry mouth were asked a standardized series of questions regarding dry mouth-related symptoms and behaviors. Whole salivary flow rates were measured under unstimulated and stimulated conditions. After using CMC-based artificial saliva for 2 weeks, each patient completed the same questionnaire. Use of the artificial saliva decreased the severity of 'oral dryness at night or on awakening', 'oral dryness at other times of the day', and 'the effect of oral dryness on daily life' (P<0.05). Patients with an undetectable flow rate of stimulated whole saliva responded better on 'oral dryness during eating' compared with the other patients (P<0.05). The use of CMC-based artificial saliva also improved dry mouth-related behaviors, especially 'awakening from sleep at night because of oral dryness'. In conclusion, CMC-based artificial saliva demonstrated moderate effects in reducing dry mouth-related symptoms and behaviors with more significant effects appearing in patients whose residual secretory potency was severely compromised.