Oral mucositis is a common symptomatic complication associated with hematopoietic stem cell transplantation (HCT). We use simple strategies aimed to reduce oral mucositis by keeping the oral cavity clean and moist. Here, we report on the progress of oral care and the changes in the degree of oral mucositis. The purpose of this pilot study is to evaluate the effects of our strategies on the prevalence and the severity of oral mucositis. Fifty-three consecutive patients from 2003 to 2006 administered with conventional allogeneic HCT were enrolled in this study. The degree of oral mucositis was evaluated daily in all patients. Our oral care program was divided into two periods: "examination and trial period (2003 and 2004)" and "intensive oral care period (2005 and 2006)." In the latter, an oral care regimen was carried out systematically by a multidisciplinary team. Using our oral care strategies, the prevalence of ulcerative oral mucositis was decreased significantly. The rate was reduced from 76% (10 of 13) of patients with ulcerative oral mucositis in 2003 to only 20% (3 of 15) in 2006. Our pilot study suggests that oral mucositis in HCT patients can be alleviated by simple strategies aimed at keeping the oral cavity clean and moist.