Tumor-associated tissue eosinophils (TATE) is a host's defensive reaction to tumor. In this study, authors examined the eosinophil of 40 squamous cell carcinomas of buccal mucosa. Infiltration of the primary tumor by eosinophil was found to have marked prognostic significance. High-grade TATE was associated with the absence of head and neck lymphonode's metastasis (P < 0.05). There was a statistical significance (P < 0.05) that high-grade TATE was a favorable prognostic indicator for squamous cell carcinoma of the buccal mucosa. Authors concluded that quantitative assessment of eosinophils was one of the most important aspects of the microscopic evaluation of this human carcinoma.