For evaluation of immune stimulation effect of lacquer tree extracts, lymphocytes were counted by labeling of FITC-conjugated monoclonal antibody in the pheripheral blood of pigs that fed with a fodder supplemented by lacquer tree extracts. Populations of MHC-II+, CD4+, and CD8+T lymphocytes were increased more than 2% level after 1 week feed supply of the lacquer tree extracts. The increase of those T cells reached at maximum level after 2 weeks in the tested group. B lympyocytes with surface IgM were increased 5% after 1 week feed supply of the lacquer tree extracts, and their numbers reached maximum after 2 weeks in the tested group. For the assessment of cytotoxicity of the lacquer tree extracts, morphological changes were examined on the epithelial cells of small intestine from pigs fed with a fodder supplemented by 0.1 % lacquer tree extracts for 6 weeks (the tested group). Thin-sectioned tissue of small intestine was fixed with glutaraldehyde, then coated with gold particles, and the specimen was examined under scanning electron microscope. The villi on the mucus membrane of jejunum and ileum from the tested pigswere enlarged on the tip and were linked each other.