The common cold, influenza, allergies and even cancer have one thing in common…the immune response. The immune system is a complex network of cells and secretory chemicals designed to protect our bodies against the invasion of foreign substances including bacteria, viruses and fungi. Despite the well intentions and overall importance, sometimes thing can go wrong contributing to a host of health problems not only for ourselves, but our pets and equine companions. As a veterinarian, a high percentage of problems in our patients can be contributed to what is termed ‘immune dysfunction’, but the ultimate question lies in how these problems are best managed to improve overall health and performance. The same problems are often encountered in people additionally, leaving an open door for desirable means of supporting the immune response.