To the best of our knowledge, from the clinical trials using double-blind randomized controlled method, no side effects were reported at our recommended dosage (two AstaDaily per day). Besides the health benefits, we receive and record customers reporting "side-effects" from time to time, but none of them are statistically significant and no placebo or control method were used. These side-effects are list below with estimated percentage of customers: increased bowl movement (~4%); red stool (~1%);  Irregular menstruation cycle (~0.1%); gain in weight (~0.05%).