Piriformis syndrome is a pain-causing disease of the sciatalgic type, also called false sciatalgia. Indeed, it is possible that a suffering of this muscle, caused by different etiologies, is responsible for a more or less pronounced sciatalgic pain. All this in the absence of overtly pathological problems such as a disc hernia, a canalized stenosis or a mass in a ischio-crural region. We dealt with this problem in a group of patients who had been submitted to various therapies in the immediately preceding periods: pharmacology, tecartherapy and manual physiotherapy. After these treatments, these subjects had the same painful symptoms without any improvement. Therefore, they were treated with oxygen ozone by infiltration. Evaluation according to the visual analog scale, baropodometric examination and clinical trials of Freiberg and Page and Nagle were performed before, in the middle, and at the end of the treatment. The results were very encouraging, showing a noticeable improvement until the disappearance of symptoms.