The effect of substance produced by honey bees on adults who complain of mouth dryness even though normal saliva flow rate

INTERVENTION: We administrate the tablet 'The enzyme‐treated Royal Jelly ‐containing tablet' named as tablet A and the tablet 'Placebo tablet (enzymatic‐degraded royal jelly‐free tablet )' named as tablet B. Tablet A and B are made and sold by Yamada Apiary, Inc. The tablet A and the tablet B have the same tablet shape and color so that the tablets' shapes and color are indistinguishable between the two drugs. Group1 The enzyme‐treated Royal Jelly are received two tablets once a day(after breakfirst ) for 12 weeks, and take wash out period for 4 weeks, then, the placebo tablets are administeredtwo tablets once a day(after breakfirst ) for 12 weeks. Group2 The the placebo tablets are administeredtwo tablets once a day(after breakfirst ) for 12 weeks, and take wash out period for 4 weeks, then, enzyme‐treated Royal Jelly are received two tablets once a day(after breakfirst ) for 12 weeks. CONDITION: Mouth Dryness PRIMARY OUTCOME: Evaluation of mouth dry feeling:; We use VAS scale. SECONDARY OUTCOME: Evaluation of psychological status: We use the Japanese version of Hospital Anxiety and Depression Scale (HADS) for evaluation.; ; Evaluation of General Health status: We use the Japanese version of General Health Questionnaire 12(GHQ12) for evaluation. INCLUSION CRITERIA: Adults who satisfy all of the following 1) to 5) 1)Adults with chief complaints of dry mouth feeling are over the age of 20 and can visit our department. Also, written consent of participants can be obtained. 2)Adults with chief complaints of dry mouth feeling and also within the normal range and excluded from xerostomia in the saliva secretion test. 3)Adults with chief complaints of dry mouth feeling and also with exclusion of autoimmune diseases including Sjogren's syndrome, salivary gland disease. 4)Adults with chief complaint of dry mouth feeling and also without systemic disease which has been treated or been followed up at the start point of this study. 5) Adults with chief complaints of dry mouth feeling and also do not have taken Royal Jelly products at the start of this study.