To evaluate three natural products with potential diuretic effect, Elephantopus scaber, Alpina speciosa and Tradescantia diuretica it was performed a trial of acute administration in 10 healthy volunteers, with interval of 7 days for each dose, except Tradescantia diuretica which was administered with 60 days of interval. All groups were compared with placebo group. The three products were given doses 5 times higher than the usually preconized by the popular use, i.e., 7.5 g/100mL, 0.8g/100mL and 25g/100mL of water, respectively. Besides physical examination, plasmatic and urinary parameters of sodium, potassium, uric, acid, calcium, phosphate, urea, creatinine and total urinary volume were evaluated. The only significant data were a light increase in diuresis (p < 0.05) with Alpinia speciosa, which also lowered the mean diastolic (p < 0.05) and systolic (p < 0.01) blood pressure. We did not found any effect in electrolytes excluding therefore, a tubular effect of these teas in modifying Na, K, Ca, P and uric acid excretions, as well as any detectable glomerular action since no changes were observed in renal function parameters.