Quantum Health Cold & Flu combines the wholesome power of echinacea, goldenseal, elderberry and vitamin C. Echinacea is an herb best known for stimulating the immune system. Often combined with echinacea, goldenseal is a traditional favorite of American Indians to support the respiratory tract. Elderberry is a powerful antioxidant and delivers bioflavonoids to the body. Vitamin C is one of the most popular immune boosting natural products: it jumpstarts your natural defenses and protects against free radicals.