Abstract: OBJECTIVE To investigate the preventive effects of Glechoma longituba extract on experimental renal calculus in rats, and explore its mechanism. METHODS The rat model of renal calcium oxalate stones was induced by administrating ethylene glycol and ammonia chloride. The 24 h urinary output coefficient and histopathological status of kidneys, the serum calcium levels, the renal tissue calcium and oxalic acid contents were detected. RESULTS G. longituba extract could markedly increase the 24 h urinary outputs and decrease the calcium oxalate deposits in the kidneys and the pathological change degrees of the kidneys. The serum calcium levels were decreased significantly. The renal tissue calcium and oxalic acid contents were decreased significantly. CONCLUSION G. longituba extract can increase the urinary output, improve the elimination and metabolism of Ca2+ in the blood and kidneys, decrease the damage caused by the renal stone, and obviously inhibit the formation of the kidney calcium oxalate stone in rats.