Kidney stones are not only a widespread problem now, but have been for centuries. Many of the plants used historically have now been found to be effective in reducing risk and reducing stone size in modern clinical trials. Both reducing stone size and reducing recurrence of stones after removal are important. Certain medical plants have been shown to slow the formation of calcium oxalate crystals. Several of these medical plants also have antioxidant and antimicrobial effects. The plants with the best clinical trials and supporting preclinical data showing effectiveness in reducing kidney stone formation and recurrence are Nigella sativa (black cumin seed), Dolichos biflorus (horse gram), Crataeva nurvala (varuna bark), and Tribulus terrestris (Gokshura). Some of these medical plants have been compared to tamsulosin (Flomax®) and potassium citrate for safety and effectiveness. Reviewed here are 11 medical plants with good clinical data, as well as 24 more plants with preclinical data or historical use.