Hailing from Germany, Esberitox is an all-natural herbal supplement that has been used in Europe for decades as an immune system booster. Combining two powerful immune-enhancing herbs, Thuja and Baptisia, with two different types of echinacea, this potent little pill strengthens the body's own natural defenses and can help prevent against the flu and common cold. While Esberitox is best taken for several weeks at a time as a preemptive measure, it can also be taken at the onset of symptoms to stimulate the production and activity of infection-fighting cells.