The present invention relates to a nasal device for modifying the nasal airflow comprising a flexible toroidal structure (1), suitable to be inserted into the subjects nasal cavities, separating the tissues of the nasal anatomy. The device comprises a closing element (2) connected to the toroidal structure (1), equipped with means to alter the shape of said toroidal structure (1), causing it to adopt a new form comprising at least two lobes (1, 1"), each of which can be inserted into a subjects nasal cavity. When the device is inserted into the subjects nasal cavities, the closing element (2) is arranged in the lower external region of the nose between the two nostrils, and each of the lobes (1, 1") of the toroidal structure (1) presses against the inner surface of the nasal cavities.
