a new application of prickly pear flowers and its derivatives in the treatment and prevention of calcium mediated lithiases (57, a lot of people in the world suffer from problems decalculs urinary. these calculations are usually made of decalcium oxalate monohydrate (com) and calcium oxalate dihydrate (ocd).in this study, the crystals of cmo were reconstructed enmu00e9langeant and stirring equal volumes of solutions of calcium oxalate (2ml / 1omm.we also added options to inhibitors of cristauxd'com mixture then evaluates the activity of the inhibitor by the aggregate crystals or crystals in a cell by observing under the light microscope and the mallassez magnification. inhibitors of crystals are obtained by pendant24h com decoction in water.