**Abstract**

Oregano essential oils (OEOs) are volatile compounds obtained from the leaves of the oregano plant (*Origanum vulgare*) through a process of steam distillation. Its major bioactive compounds include carvacrol and thymol. The OEOs from *Origanum* spp. have been considered to be the best ones because they have a higher content of carvacrol; however, in tropical America and Africa ecosystems, chemotypes with a high thymol content are found as *Lippia origanoides*. Carvacrol and thymol are responsible for the strong antimicrobial, antioxidant, and anti-inflammatory effects of OEO. They have been studied for their potential effects on the function of intestinal barrier, which plays a crucial role in maintaining gut health. These compounds may help reduce inflammation in the gut, protect and preserve intestinal integrity, control the growth of harmful bacteria in the gut, and improve the poultry's productive performance. The OEO has potential as a natural alternative to antibiotics for improving intestinal health and barrier function in poultry. However, more research is needed to fully understand the mechanisms underlying these effects and determine the optimal dosage and duration of OEO supplementation.

**Keywords:** *Lipia origanoides*, *Origanum*, thymol, carvacrol, growth promoter, nutraceuticals
