For more than 30 years, best-selling author and popular herbalist Rosemary Gladstar has been touting the health benefits of fire cider -- a spicy blend of apple cider vinegar, onion, ginger, horseradish, garlic, and other immune-boosting herbs. Her original recipe, inspired by traditional cider vinegar remedies, has given rise to dozens of fire cider formulations created by fans of the tonic who use it to address everyday ills, from colds and flu...