Phytogenics,however, are a relatively new class of feed additives and our knowledge is still rather limited regarding their modes of action and aspects of their application. Further complications arise because phytogenic feed additives may vary widely with respect to botanical origin,processing, and composition. Most studies investigate blends of various active compounds and report the effects on production performance rather than the physiological impacts. In this context, the following provides an overview of recent knowledge on the use of phytogenic feed additives in piglet and poultry diets,possible modes of action, and safety implications.