Please don't think I've posted the info below to deliberately frighten people, but I think users of spiro should read it, research further, and then make their own minds up. I have my first box of tablets here, which my doctor prescribed yesterday. I am going to give the meds a miss, as for me, the risks outweigh any possible benefits, which aren't guaranteed in the first place. Carcinogenesis, mutagenesis, impairment of fertility Orally administered Aldactone (spironolactone) has been shown to be a tumorigen in dietary administration studies performed in rats, with its proliferative effects manifested on endocrine organs and the liver. In an 18-month study using doses of about 50, 150 and 500 mg/kg/day, there were statistically significant increases in benign adenomas of the thyroid and testes and, in male rats, a dose-related increase in proliferative changes in the liver (including hepatocytomegaly and hyperplastic nodules). In a 24-month study in which the same strain of rat was administered doses of about 10, 30, 100 and 150 mg Aldactone (spironolactone) /kg/day, the range of proliferative effects included significant increases in hepatocellular adenomas and testicular interstitial cell tumors in males, and significant increases in thyroid follicular cell adenomas and carcinomas in both sexes. There was also a statistically significant, but not dose-related, increase in benign uterine endometrial stromal polyps in females. A dose-related (above 20 mg/kg/day) incidence of myelocytic leukemia was observed in rats fed daily doses of potassium canrenoate (a compound chemically similar to Aldactone (spironolactone) and whose primary metabolite, canrenone, is also a major product of Aldactone (spironolactone) for a period of one year. In two-year studies in the rat, oral administration of potassium canrenoate was associated with myelocytic leukemia and hepatic, thyroid, testicular and mammary tumors.