Traditional horned cattle phytotherapy in the Rusizi plain breedings [Rwanda, Burundi, Democratic Republic of Congo]. After presenting the ecological characteristics of the Rusizi plain and reminding of the socio-economical importance of horned cattle for the local populations, the authors deal with the traditional phytotherapy knowledge in this area. The study lists the plants used, the organs concerned (leaves, bark, root, fruit, etc.), as well as the formula and doses recommended regarding the recognized diseases. Finally this ethnobotanical knowledge is placed and discussed regarding the East African one.