Background: Oral lichen planus and mouth dryness are common pathoses, yet not entirely understood. These two conditions may be associated, with a few studies investigating the relationship between mouth dryness and oral lichen planus providing conflicting results. None of the studies have explored the specific impact of disease treatment on mouth dryness. Objective: The purpose of this observational before and after comparison study was to examine the effect of treatment of oral lichen planus with topical corticosteroids on mouth dryness. Methods: Nineteen subjects with oral lichen planus were evaluated for the severity of xerostomia using a xerostomia inventory and a visual analogue scale. Stimulated and unstimulated whole salivary flow rates, unstimulated salivary pH and buffering capacity were also measured. All subjects were evaluated before and after treatment with topical corticosteroids. Results: All subjects reported xerostomia before treatment with topical corticosteroids, with 79% reporting a significant improvement (P = 0.03) after treatment. Topical corticosteroid treatment was not associated with statistically significant differences in stimulated or unstimulated salivary flow rates, unstimulated salivary pH or buffering capacity. Conclusion: The results of this study suggest that treatment of oral lichen planus with topical corticosteroids may decrease the severity of dry mouth symptoms.