Functional foods provide health benefits if they are consumed on regular basis. Some nutraceutical pet diets have been demonstrated to exert health benefits in vitro and in vivo while also exhibiting palatability to the animals. The aim of this chapter is to provide an overall update of commercially available pet diets with proven efficacy against pathologies with an inflammatory background. Research on pet food is still scarce and biased. The ultimate success of functional pet foods will depend on delivering bioactive components in a predictable and assured manner to effectively reduce the risk of disease and/or support the body. Our investigations outlined the improved health status of sick dogs by means of a commercially available nutraceutical pet diet approach. Therefore, additional investigations into the consumption of functional foods in domestic animal nutrition should be done in order to study dietary interventions for disease prevention and treatment.