Using HÜBNER Immun PRO Infection Blocker regularly supports the body’s natural immune system. The standardised special extract of cistus villosus contains a high level of polyphenols (up to 300 mg per daily dose). The polyphenols (tannins) in the cistus villosus extract coat the mucous membranes in the mouth & throat, thus helping to ward off cold viruses. This physical effect means that no resistance is built up. The cistus villosus extract used in this product is obtained from cistus villosus (rockrose) harvested in the wild.