**7. Conclusions**

This chapter has shown that monoterpenes, sesquiterpenes and their derivatives, aromatic compound, and compound of various origins are the main chemical constituents of essential oils identified in plants. Several reports demonstrated that EOs exhibit a range of pharmacological actions, such as antiulcer, hepato-nephroprotective, anti-inflammatory, antidiabetic, antioxidant, antibacterial, antifungal, and anticholinesterase activities, supporting their traditional uses. In addition, essential oils exerted beneficial effects on nutrient digestibility and intestinal function in broilers, improved digestibility parameters in ruminants, as well as decreased NH4 + emissions.

However, further improvements are needed to adjust the doses of inclusion/ administration because misuse can lead to severe human and animal toxicities. Finally, it is strongly recommended to keep these bioactive molecules well and to keep them away from children.
