目的　用乳糖H2 呼吸试验测定正常人群的OCTT。方法　用CM型微量H2 分析仪 ,采用Solomon氏方法 ,以 18克乳糖为底物对 10 9例乳糖吸收不良者作BHT ,测定口服乳糖到肺泡气含H2 2 0ppm所需的时间 ,即OC TT。结果　 10 9例正常人群的OCTT为 117.89± 3 3 .64min。男性 117.71± 5 4min ,女性 116.71± 2 5 .2 5min。意义　利用 18克乳糖作底物作BHT测定OCTT是较为准确的方法 ,简便无损害 ,易被接受 Objective To determine the OCTT of normal subjects by lactose H2 breath test. Methods Using the CM trace H2 analyzer, Solomon’s method was used to measure the time required for oral administration of lactose to alveolar gas containing H2 0 0ppm, using 18 g lactose as substrate for 109 cases of lactose malabsorption. . Results The OCTT of 109 normal subjects was 117.89 ± 3.34min. Male 117.71 ± 54min, female 116.71 ± 2.52.5min. Significance The use of 18 grams of lactose as a substrate for the determination of OCTT BHT is a more accurate method, simple and easy to damage, easily accepted