Objective To observe the gamma-glutamyltransferase ( GGT) activity and total antioxidant capacity ( T-AOC) in serum and platelet during the course of community-acquired pneumonia ( CAP) . Methods Ninety cases of hospitalized CAP were recruited from the respiratory wards in the Affiliated Hospital of XuzhouMedical College fromSeptember 2010 to September 2011, and 30 healthy cases who underwent physical examination in the same hospital were enrolled as control. GGT activity and T-AOC were compared between the CAP patients and the control subjects, and also between the CAP patients who developed reactive thrombocytosis ( platelet count gt;300 ×109 /L) and those without thrombocytosis ( platelet count ≤300 ×109 /L) . Results Compared with the control subjects, serumand platelet GGT activity of the CAP patients were significantly higher [ ( 45. 6 ±25. 4) U/L vs. ( 17. 9 ±3. 7 ) U/L, ( 179. 9 ±41. 3) mU/109plt vs. ( 49. 5 ±8. 0) mU/109plt, P lt; 0. 05] , serum T-AOC at admission was significantly lower [ ( 12. 6 ±1. 6) U/mL vs. ( 17. 7 ±2. 1) U/mL, P lt; 0. 05] , and platelet T-AOC at admission was significantly higher [ ( 61. 6 ±18. 3) mU/109plt vs. ( 48. 6 ±9. 9) mU/109 plt, P lt; 0. 05] . Platelet T-AOC of the CAP patients at discharge was significantly lower than that of the CAP patients at admission and the control subjects. Compared with the CAP patients without thrombocytosis, serum T-AOC and serum GGT activity of the CAP patients who developed reactive thrombocytosis were significantly higher( P lt;0. 05) , and platelet T-AOC and platelet GGT activity were both significantly lower ( P lt; 0. 05) . There were negative correlations of the platelet count with platelet T-AOC and GGT activity in the CAP patietns( r = - 0. 316,P =0.003; r = - 0. 318, P =0. 002) . Conclusions There is a correlation between the oxidative stress and the platelet function in the inflammatory process of CAP. There might be an indicative role of platelets in resolving the inflammatory process and in maintaining the oxidative-antioxidative balance.