Abstract: The UHPLC-LTQ-orbitrap-MS metabolomics technique was used to determine the effect of deapio-platycodin D (DPD) on endogenous metabolites in lung tissues of mice with ammonia-induced cough, and to identify the metabolic regulatory pathways of DPD in its antitussive and expectorant activities. This work was approved by the Animal Ethics Committee of Jiangxi University of Chinese Medicine (Approval No. JZLLSC-20190235). Metabolites were identified by UHPLC-LTQ-orbitrap-MS method and the metabolic pathways related to differentially-expressed metabolites were analyzed by the MetaboAnalyst platform. DPD significantly prolonged (P < 0.05) cough latency, reduced the number of coughs, and significantly increased (P < 0.05) phenol red excretion in ammonia-induced cough mice. Twenty-five metabolites related to cough and 38 metabolites related to sputum excretion were identified by UHPLC-LTQ-orbitrap-MS. Changes in the metabolism of linoleic acid, arachidonic acid, glycerophospholipid, alanine, aspartic acid and glutamic acid, pentose and glucuronate interconversions, and lysine degradation were evident with DPD treatment of ammonia-induced cough mice. Changes in the metabolism of linoleic acid, taurine and hypotaurine, glycerophospholipid, purines and pyrimidines, arachidonic acid and the biosynthesis of unsaturated fatty acids after DPD treatment were related to phenol red excretion. Linoleic acid metabolism, arachidonic acid metabolism and glycerophospholipid metabolism are common regulatory pathways by which DPD appears to exert its antitussive and expectorant activity. These metabolic pathways are closely related to anti-inflammatory pathways, immune function regulation, neurotransmitter release, cell signal transduction, energy metabolism and apoptosis. This study clarifies the antitussive and expectorant activity and mechanism of DPD.