Hippocrates, the ancient Greek physician known as the father of modern medicine, affectionately called elderberry his “medicine chest.” The flowering shrub—which sprouts bright, antioxidant-rich berries that contain potassium, calcium, and vitamins C and D—has been used for centuries to remedy a range of conditions including the flu, insect bites, and toothaches. Since the seeds of the tangy fruit are toxic, elderberries must be cooked before they’re eaten, and often take the form of jams, syrups, and lozenges.