Edible plant Trianthema monogyna (TME) and the Pulse Macrotyloma uniflorum (KPE) extracts were found to be effective in the inhibition of calcium oxalate crystallization. Various physicochemical techniques, viz. conductometric and nephelometric titrations, UV-vis and IR spectroscopy and potential measurements in the absence and presence of these extracts were employed. TME and KPE both reduced the particle size considerably from 250 to 5-50 mum range as revealed by microphotographs. Considerable solubility in the presence of TME and KPE was also observed by flame photometric studies. Dissolution was found to vary with time. Particle size distribution in CaC2O4 precipitate may be one of the reasons. (C) 2004 Published by Elsevier B.V.