目的：探讨多抗甲素对小儿反复呼吸道感染的疗效，并观察治疗前后免疫指标的变化。方法：治疗组 ３１例（男性 １８例，女性 １３例；年龄 ３８ｍｏ± ｓ８ｍｏ）在常规治疗（如抗生素类或抗病毒类药物及对症治疗，不用激素或其他影响免疫功能药物）的基础上加用多抗甲素，年龄＜２ ａ，每次２．５ ｍｇ， ３～５ ａ每次 ５ ｍｇ，≥６ ａ每次 １０ ｍｇ，加， ｔｉｄ×１ ｍｏ；对照组 ２７例（男性 １５例，女性 １２例，年龄 ３１ ｍｏ± ６ｍｏ）；同治疗组相似的常规治疗。结果：２组总显效率分别为 ９０％和 １５％，治疗组治疗后 ＩｇＧ和 ＩｇＡ均较治疗前提高，ＰＨＡ反应增强。结论：多抗甲素防治小儿反复呼吸道感染疗效好而安全，免疫功能提高。 Objective: To investigate the efficacy of poly-A against children with recurrent respiratory tract infections and to observe the changes of immune indexes before and after treatment. Methods: 31 cases of treatment group (18 males and 13 females; age 38mo ± s8mo) in the conventional treatment (such as antibiotics or anti-viral drugs and symptomatic treatment, without hormones or other effects of immune-functional drugs) based on the use of Poly A, age <2 a, each 2.5 mg, 3 ~ 5 a each 5 mg, ≥ 6 a each 10 mg, plus, tid × 1 mo; control group of 27 patients (15 males, 12 females, age 31 mo ± 6 mo); similar treatment with the conventional treatment group. Results: The total effective rates of two groups were 90% and 15% respectively. The IgG and IgA in the treatment group were significantly higher than those before treatment and the PHA responses were enhanced. CONCLUSION: Polyactin A is effective and safe in preventing recurrent respiratory tract infections in children, and its immune function is improved.