The purpose of the current trial is to investigate the effect of herbal extract granule named Yukmijihwang-tang (YMT) on dry mouth. The trial is a randomized, double-blinded, placebo-controlled, 2-arm, 2-centered study. Ninety-six patients with xerostomia will be randomly assigned to one of the 2 groups consisting of YMT or placebo. The assigned treatments will last for 8 weeks and the follow-up period will be 2 weeks.