A 77-year-old woman with nephrotic syndrome secondary to idiopathic membranous nephropathy was treated with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, cyclosporine A, and mycophenolate mofetil, without response. After more than 2 years of unremitting nephrosis, she began therapy with the herb Astragalus membranaceus, used by traditional Chinese physicians to treat various immune disorders, including glomerulonephritis. After institution of Astragalus at a dose of 15 g/d, there was a marked decrease in proteinuria. Nephrotic syndrome recurred after temporary cessation of Astragalus therapy, with complete remission of nephrosis observed after its reintroduction. The clinical course of this patient suggests that Astragalus may have beneficial effects in patients with idiopathic membranous nephropathy.