Context: In Africa, medicinal plants are usually used to treat diarrhea but few data are available concerning their identification and their antidiarrheal activities. Aims: This study aims to record some antidiarrhoea plants in the Medoneu locality (Gabon), describe their modalities of use and assess the chemical composition and antibacterial activities of four most commonly used plants. Methods and Material: Plants and their modalities of use were recorded through ethnobotanical survey. Four commonly used plants were harvested; their extracts and the essential oils (EO) were prepared from the leaves by maceration and hydro-distillation. The chemical compositions of EO were determined by Gas Chromatography while, the antibacterial activities of extract and EO were assessed using both agar diffusion and micro-dilution methods.