This research was performed to encapsulate the phenolic-rich fraction (PRF) obtained from Ferula gummosa (F. gummosa) leaves by utilizing the spray-drying technique.Further, the physicochemical properties and antioxidant and antibacterial activities of the PRF were evaluated against Campylobacter jejuni (C. jejuni) infection in mice. The results showed that the PRF encapsulated in modified starch, maltodextrin, and whey protein concentrate as wall material possessed a capsulation efficiency of 83.7% with a particle size of 314.6 nm. The phytochemical analysis of developed phytobiotic confirmed the presence of phenolic compounds, including gallic acid, vanillic acid, pyrogallol, cinnamic acid, ellagic acid, naringin, and chrysin. The developed phytobiotic could potentially improve the growth parameters, liver enzymes, and lipid peroxidation, enhance the ileum's morphometric parameters, and inhibit the ileal population of C. jejuni in the mice challenged by C. jejuni infection. Consequently, the phytobiotic developed based on F. gummosa leaf phenolic compounds could be considered a promising natural alternative to antibiotics.