The increase in MMP-1, MMP-2, MMP-8, and TIMP-1 levels in Mucositis rats’ sera and stomach, small intestine and large intestine were significantly suppressed in Mucositis + ALA rats (p < 0.05–0.0001), although there was no significant difference in serum MMP-8 levels between the Mucositis + ALA and Mucositis groups. Here, MMP8 is linked to mucositis.