Methods for treating and preventing mucositis, in particular mucositis following the administration of chemotherapy drugs or a combination of said drugs with radiotherapy, are disclosed herein. More specifically, disclosed herein is the administration of a therapeutically effective amount of at least one of an anthocyanoside, a proanthocyanidin, or an extract containing at least one of an anthocyanoside or a proanthocyanidin (especially A2 abd B2) for the treatment or prevention of mucositis. The therapeutically effective amount of the anthocyanoside, proanthocyanidin or extract can be administered alone or in combination with a therapeutically effective amount of at least one of an anti-inflammatory agent, immunomodulating agent, analgesic, antimicrobial agent or antifungal agent. Also disclosed herein are pharmaceutical compositions for treating and preventing mucositis.
