To study the chemical constituents in Periplaneta americana.The chemical constituents were separated and purified by chromatographic methods after solvent extraction and identified by spectroscopic analyses.Ten compounds were isolated from Periplaneta americana and identified as following: 8-hydroxy-3,4-dihydroquinolin-2 (1H)-one (1), cyclo-( L-Phe-L-Pro) (2), cyclo-(Pro-Ile) (3), cyclo-(L-Pro-D-Leu) (4), brevianamide F (5), cyclo-(Ile-Ala) (6), cyclo-( L-Val-L-Pro) (7), cyclo-(L-Pro-L-Tyr) (8), cyclo-(Trp-Val)-dipeptide (9), and (-)-(1S, 3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (10).Compounds 2 - 9 are isolated from Periplaneta americana for the first time.