As the herb Cyperus stoloniferus of Vietnam (botanically, described as perenial 20-30cm high; leaves narrow and long, one nerved; inflorescence of spikes, radiating, purplish; fruit angular) provide wild weeds and rhisomes, both in decotion produce emmenagogic, stomachic, antidiarrheic and antiemetic effects, the essential oils therefrom were investigated on chemical compotion. The oil yield of the rhiromes was 0.62 percent (on air-dried material). By GC/MS, 28 compounds were identified; of which the main ones were alpha-cyperon (32.37 percent); beta-selinen (7.34 percent); 1.4-ethanoazulen-7-onoctahydro-4-8-tetramethyl (6.1 percent); 2-cyclohexen1-ol-2-methyl-5 (5.95 percent) and caryophyllenoxid (3.68 percent).