Engystol® Indication Be healthy and strong! Engystol is a homeopathic preparation which has been scientifically proven to significantly reduce the duration and severity of symptoms during an acute viral infection and help protect from subsequent infections.Engystol® is a safe, doctor-recommended medicine designed to support the immune system against the symptoms of flu, including fever, body aches and chills. Appropriate for all ages, Engystol® is regulated by the FDA, has no known side effects, and is safe to take in conjunction with other medications. Our advice for this flu season is simple: Be informed. Be prepared. Be healthy. Engystol in one of Heel's top selling immune-boosting homeopathic formulas, especially for viral infections such as cold and flu. With active homeopathic Asclepias, Engystol also contains a blend of remedies to provide effective anti-viral support for stimulation of the nonspecific defense system in viral infections such as: influenza, cold sores, feverish conditions.