The general objective was to evaluate the in vitro activity on Salmonella enterica of typhi stereotype of plant drugs used in the treatment of typhoid fever. The crop drugs harvested were processed and dried for three weeks. After maceration in ethanol, the crude extracts were concentrated using a rotary evaporator and a phytochemical screening was carried out. The antimicrobial activity of the ethanolic extracts was evaluated in vitro on Salmonella enterica of typhi stereotype, by the method of microdilution in liquid medium on microplates of 96 wells in U bottom. Seven possibilities were offered for this evaluation in the microplates: three first (E1, E2 and E3) concerned the isolated extracts and the four others (E1 + E2 + E3, E1 + E2, E1 + E3 and E2 + E3) combinated extracts. The observation of the turbidity of the microplate liquid media after 24 h of incubation allowed the determination of the minimal inhibitory concentrations (CMI) and the seeding of the wells on solid media HEKTOEN and EM allowed the determination of the minimal bactericid concentrations (CMB). Characterization of the different groups of secondary metabolites in isolated ethanolic extracts revealed the presence of phenols, steroids, triterpenes, coumarins and alkaloids. Isolated extract of Costus afer showed a very low CMI and CMB with values of 0.07 and 0.15 mg/mL and was more active on Salmonella enteric typhi stereotype than the other two isolated extracts. Combination of Costus afer and Annickia chlorantha (E1 + E3) stems showed low CMI and CMB with values of 0.15 mg/mL and were more active on S. enterica of typhi stereotype. The combinated extracts showed CMB values between 0.15 and 0.60 mg/mL versus 0.15 and 1.25 mg/mL for the isolated extracts. Analysis of CMI and CMB has shown that combinated extracts have more effective antibacterial activities than isolated extracts because of the positive interactions between bioactive contents involved, and should be considered in in vivo pharmacological activities in rats.