RESUMEN
Jinyingzi is the dry ripe fruit of Rosa leav gata Michx.. It contains mainly tannic acid, malic acid, citric acid, vitamin C and saponins. Its effect on urinary sy stem was studied on mouse Pollakiuria model by severing hypogastric nerve. Results showed that the water extract of R. laevigata can decrease the frequency and prolong the interval of urination and increase the quantity of eacn urination. The said extract can inhibit the automatic contraction of isolated rabbit jejunal smooth muscle and antagonize the spasmodic contraction arouscd by acetylcholine and barium chloride of isolated rabbit jejunal smoothmusele, and isolated vesical smooth muscle of mouse, and antagonize reaction of contractility aroused by noradrenalin on isolated thoracic aorta strips of rabbit. All of the the three inhibitions of smooth muscle contraction showed signicant dose-response curve.