The invention provides a nipple, which relates to the technical field of medical appliances, comprising a nipple body with a U-shaped structure, a tongue pressing part connected with the nipple body for restricting the movement of the tongue, and the tongue pressing part has a communication channel communicating with the outside. By setting the nipple as a U-shaped structure, that is, a tooth-shaped structure, so that the nipple covers the whole tooth, and the existing nipple is an ordinary O-shaped nipple, the wrapping property is not strong, only the movement of the incisor teeth is restricted, the comfort is poor, and the endoscope is easy to be damaged by the patient, thereby affecting the treatment. The bite nozzle provided by the invention is a U-shaped structure, that is, the bite nozzle is arranged in an oral structure, so that when in use, the bite nozzle covers the whole tooth, the teeth between the upper row and the lower row are no longer in contact, the comfort degree is higher, the endoscope is not easy to be damaged, and the treatment can be smoothly carried out.