La "yerba del pollo" (Alternantitera pungens H.B.K., Amarailthaceae) es ampliamente usada en medicina popular en los trastornos gastrointestinales. Se investigaron los componentes fitoquímicos relacionados a la actividad purgativa de su fruto. Se detectaron en el fruto antraquinonas como O-glicósidos y C-glicósidos. Asimismo se aislaron dos heterósidos saponínicos, cuyas geninas fueron el ácido oleanólico y el β-sitosterol, en tanto que el glicón es glucosa. Por otro lado se encontraron dos bases de amonio cuaternario, colina y acetilcolina. Con el extracto del fruto se realizaron estudios farmacológicos relacionados a su actividad purgativa. Los resultados obtenidos confirman el uso popular de esta planta.Altertiatithera pitngens H.B.K. (Amaranthaceae), commonly known as "yerba del pollo", is widely used as a folk medicine. Its fruits were submitted to phitochemical investigations and tested for purgative activity. Anthraquinone O-glycosides and C-glycosides were detected in the fruit. Two saponin heterosides were also isolated, whose genines were oleanolic acid and β-sitosterol, with glucose in both of them as its glycosidic moiety. Two ammonium quaternary bases, choline and acetylcholine, have been detected. The extracts of fruits were prepared and tested for pharinacological effects (purgative activity). The results seein to correlate with the local use of the plant.