May aid the kidney in the elimination of water Kidney Tonic combines four herbs which work synergistically in the body and may help to maintain the health of the urinary tract, aid detoxification by supporting the body's natural elimination of toxins and impurities and support bladder health. Apart from Solidago (Solidago virgaurea) the herbs present in this fresh herb tincture are Birch (Betula pendula), Restharrow (Ononis spinosa) and Horsetail (Equisetum arvense).