Oropharyngeal cannula (1) including a body (2) formed by a distal part (2d) which is curved in order to be inserted into a patients mouth and to immobilize his tongue and by a proximal part (2p) including a collar (3) which can rest on the patients lips, a main duct (5) forming a passage for fluid between the proximal part and the distal part of the body, and two auxiliary ducts (6, 7) which are formed in the body and extend from the proximal part (2p) as far as into the main duct. Each auxiliary duct opens into the proximal part of the body over an input/output orifice (64, 74) which is oriented in a direction which is radial relative to the axis of the main duct, such as to be oriented laterally on either side of the patients mouth when the cannula is installed on the patient.