Chemotherapy-induced oral mucositis (COM) is a common adverse effect of cancer chemotherapy. Several clinical studies reported that repetitive use of mouthwashes containing 2.5–6.25% Hangeshashinto (HST), a Kampo formula, relieves COM, but the effect is insufficient. To solve this problem, we produced an oral ointment of 12% HST extract (considered quantitatively equivalent to 20% commercially available HST), which will increa...