Abstract: The aim of this study was to review research currently being carried out on the herbal plants and phytogenics that have been shown to modulate the immune system and special attention is given to the use of herbal plants on poultry herbal feed supplement. The uses of herbal plants as health promoters are gaining increasing attention in both consumer and scientific circles. Although, there are few studies which have revealed the mechanism of action of the immunostimulatory compounds of herbal plants but the exact molecular mechanisms of some herbs are not already known. There are several possible explanations for immunomodulation mechanisms of herbal plants and their derivatives that have been put forward. Our attempt here would be to look more closely at the herbal plants mechanisms involved, including from the immunomodulation point of view, and relationships between structures and activities.