AIM:To analyze detailed changes in hematology andbiochemistry tests parameters before and after a long-distance race in ultramarathon runners.METHODS:Blood samples of 11 participants were obtainedfor standard analysis before,immediately after,two daysafter and nine days after the 2002 International Ultra-marathon 24 h Race and the International Association ofUltrarunners (IAU) Asia 24 h Championship.RESULTS:Total bilirubin (BIL-T),direct bilirubin (BIL-D),alkaline phosphatase (ALP),aspartate aminotransferase(AST),alanine aminotransferase (ALT) and lactatedehydrogenase (LDH) increased statistically significantly(P<0.05) the race.Significant declines (P<0.05) in redblood cell (RBC),hemoglobin (Hb) and hematocrit (Hct)were detected two days and nine days d after the race.2 d after the race,total protein (TP),concentration of albuminand globulin decreased significantly.While BIL,BIL-D andALP recovered to their original levels.High-density lipoproteincholesterol (HDL-C) remained unchanged immediately afterthe race,but it was significantly decreased on the secondand ninth days after the race.CONCLUSION:Ultra-marathon running is associated witha wide range of significant changes in hematologicalparameters,several of which are injury related.To provideappropriate health care and intervention,the man whoreceives athletes on high frequent training program highintensity training programs must monitor their liver andgallbladder function. AIM: To analyze detailed changes in hematology andbiochemistry tests parameters before and after a long-distance race in ultramarathon runners. METHODS: Blood samples of 11 participants were obtained for standard analysis before, immediately after, two daysafter and nine days after the 2002 International Ultra- marathon 24 h Race and the International Association of Urines (IAU) Asia 24 h Championship .RESULTS: Total bilirubin (BIL-T), direct bilirubin (BIL-D), alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (P <0.05) in red blood cells (RBC), hemoglobin (Hb) and hematocrit (Hct) were detected two days and nine days d after the race.2d after the race, total protein (TP), concentration of albuminand globulin decreased significantly.Hile BIL, BIL-D andALP recovered to their original levels. High-density lipoproteincholesterol (HDL-C) remained unchanged i mmediately afterthe race, but it was significantly decreased on the second and ninth days after the race. CONCLUSION: Ultra-marathon running is associated witha wide range of significant changes in hematological parameters, several of which are injury related. To provide appropriate health care and intervention, the man whoreceives athletes on high frequency training program high intensity training programs must monitor their liver andgallbladder function.