Objective To observe effect of small and large ambroxol on pulmonary surfactant in asthma guinea-pig. Methods 24 guinea-pigs were randomly divided into 4 groups;normal control group,asthma group, small dose ambroxol(7.5mg/kg.d)treated group, large dose ambroxol(30mg/kg.d)treated group. We detected total phospholipids(TPL),desaturated phosphatidylcholine(DSPC),total protein(TP) in broncho-alveolar lavage fluid(BALF).Results The levels of DSPC/TP? DSPC/TPL and DSPC of asthma group were statistically lower than normal control group P 0.05),were statistically higher than asthma group( P