The effect of 5 plant polysaccharides injectedintraperitoneally to the peripheral T,B and thymusT lymphocytes in tumor transplanted mice irradiatedlocally by X-ray was investigated cytochemically.The peripheral T lymphocyt percentage in 5 treatedgroups of female tumor transplanted mice irradiatedlocally by X.ray dropped markedly;the B lymphocytepercentage rose in all 5 treated groups.The peri-pheral T lymphocyte percentage in groups treatedwith polyporus umbellatus,yeast Mannan,RadixAngeficae Sinensis Ⅱ and Armillaria Mellea C-D fellappreciably in male tumor transplanted mice irradiat-ed locally by X-ray;the peripheral B lymphocytepercentage in these groups increased.The injectionof yeast Mannan,Radix Angelicae Sinensis Ⅱ,Armil-laria Mellea C-D and Lichina confinis reduced thethymus T lymphocyte percentage in female tumortransplanted mice irradiated locally by X-ray.Poly-porus umbellatus increased the thymus T lymphocytepercentage in male tumor transplanted mice,whileyeast Mannan and Radix Angelicae Sinensis Ⅱ greatlylowered the thymus T lymphocyte percentage.Therelationship between the changes of the peripheraland thymus T lymphocyte percentages and the inhibi-tion of the tumor growth in tumor transplanted miceof both sexes is discussed. The effect of 5 plant polysaccharides injected intraperitoneally to the peripheral T, B and thymus T lymphocytes in tumor transplanted mice irradiated locally by X-ray was investigated cytochemically. The peripheral T lymphocyt percentage in 5 treated groups of female tumor transplanted mice irradiated locally by X.ray dropped markedly; the B lymphocytepercentage rose in all 5 treated groups.The peri-pheral T lymphocyte percentage in groups treatedwith polyporus umbellatus, yeast Mannan, RadixAngeficae Sinensis II and Armillaria Mellea CD fellappreciably in male tumor transplanted mice irradiatedat-ed locally by X-ray; the peripheral B lymphocytepercentage in these groups increased. Injection of yeast Mannan, Radix Angelicae Sinensis II, Armil-laria Mellea CD and Lichina confinis reduced theymus T lymphocyte percentage in female tumortransplanted mice irradiated by X-ray. Poly-porus umbellatus increased the thymus T lymphocytepercentage in male tumor transplanted mice, whileyeast Mannan a nd Radix Angelicae Sinensis II greatly reducedered the thymus T lymphocyte percentage. Relationshipship between the changes of the peripheraland thymus T lymphocyte percentages and the inhibi-tion of the tumor growth in tumor transplanted mice of both sexes is discussed.