The crystallization of calcium oxalate monohydrate (COM) was investigated at conditions of constant undersaturation both in the absence and in the presence of aqueous extracts of Corn Silk (Cs) and Trigonella Foenum Graecum.L (Tg) at 37oC, 0.15 M NaCl and at( σ = 0.25 - 0.6). The dependence of the rates of COM crystallization in the presence of inhibitors was found to be second order suggesting a surface controlled mechanism. The results obtained showed that the aqueous extract of (Cs)and (Tg) has biological properties that act as strong inhibitor for crystallization rates of calcium oxalate monohydrate stones. The suggestion of predominately surface Controlled mechanism is also supported by the observed low value of the activation energy Ea = 4.3 kcal/mol. The data on the crystallization kinetics of crystals in the presence of aqueous extract of (Cs) and (Tg) were examined from the stand point of adsorption models. aqueous extracts of (Cs ) and (Tg) effects were interpreted in terms of the adsorption of inhibitors on to the active growth sites on the crystal surface. In conclusion, these results have been proved the folk medicine use of (Cs) and (Tg) for kidney stones and the extracts of its may be beneficial for the treatment of nephrolithiasis but a detailed preclinical and clinical study is required.