In order to identify and isolate the active principles of medicinal plants with antibacterial activity in the Kisangani region (DR Congo), five medicinal plants including Anthonotha macrophyla, Azadiractha indica, Trema orientalis, Citrus limon and Ananas comosus have been used for this study. The objective of this study is to characterize phenotypically the 17 strains of Salmonella, for the identification, and the chemical study of the active principles of medicinal plants used in the treatment of typhoid in the city of Kisangani. Strain characterization and chemical screening were used for the detection of Salmonella and phytochemical groups present in our plants. The liquid-liquid extraction made it possible to obtain the dried extracts of the major phytochemical groups after evaporation of the solvents employed. The method of inhibiting bacterial growth by diffusion in agar medium was used to study the sensitivity of Salmonella typhi strains to extracts of medicinal plants. The results of our research reveal that the phenotypic characterization showed that there is similarity between the 17 strains of Salmonella typhi studied and the reference strain. The chemical screening revealed the abundant presence of tannins and saponins in the leaves of Anthonotha macrophylla, Azadirachta indica and in the leaf of Trema orientalis, but traces of alkaloids in the leaves of Trema orientalis, as well as very abundant presence of sterols and terpenes as well as quinone in the bark of the Citrus limon root. In addition, the extraction of the active ingredients yielded respectively the following yields: 4.92% of the leaves of Trema orientalis, and 2.48% of the leaves of Azadiractha indica and 2.44% of Anthonotha macrophylla for the leaves. saponins. As for extracts of tannins, in Azadiractha indica, 22.76% and in Anthonotha macrophylla is 14.76%, while the leaves of Trema orientalis contain only 14.44%. Determination of microbial growth inhibitory activity extracts revealed growth inhibition of Salmonella typhi strains, saponin extracts and Tanic extracts of Anthonotha macrophylla and Trema orientalis were active on microbial strains tested (Salmonella typhi) with inhibition zone diameters means 13, 14 and 16mm in diameter for Anthonotha macrophylla and extracts of Trema orientalis with inhibition diameter of 14, 12, 11, 10mm. Azadiractha indica extracts showed antibacterial activity of 11mm in diameter.