Poly-(etheretherketone) (PEEK) began to be used in the field of odontology more than 10 years ago, especially in relation to the creation of removable partial dentures. Here we report the case of a 62 years old woman diagnosed with histamine intolerance (or histaminosis), who presented a very particular set of oral symptoms. She described a certain tingling, burning, and swelling of the mucous membranes. These symptoms seem to be linked with the wearing of a resin occlusal splint which was initially prescribed to compensate for the absence of a meniscus in the left temporomandibular joint of the patient. After a multidisciplinary concertation, it was decided to create a new splint with a resin-free material. For this reason, the production of a PEEK prosthesis was considered. Following the installation of the occlusal splint in the patient, and after clinical adjustments, she described the occlusion positioning as correct and a disappearance of the symptomatology. Mechanically, PEEK seems to have higher mechanical resistance than PMMA. Despite these characteristics, the use of PEEK still presents some limitations, especially concerning the overall aesthetic. Additionally, the prescription of the occlusal splint seems to be limited to patients who need special care. The case presented here thus confirms a new perspective concerning the use of PEEK as an occlusal splint.