White Willow 1oz Alcohol Free Natures Answer White Willow Bark Extract Natures Answer Liquid Extracts are MUCH MORE CONCENTRATED than Liquid Tinctures. Â If you compare the milligrams you are getting per dose, you will notice that TWO DROPPERFULS (2 ml) are prepared from 2000 mg concentrated herbal extract! Many people are able to identify a willow tree, with its long branches that float with the wind.