Introduction and aims of the study - The aim of this study was to evaluate the efficacy and safety of Onemytis plasma device in some surgical applications, and its effect on tissue healing. Onemytis is device which uses Airplasma ® technology to transform the air column between the tip of the hand-piece and the tissue into an energy conductor, allowing incisions without direct contact. The tissue dissipation temperature is 50 °C. Materials and methods - The first phase of the study involved a comparison of the histological appearance of the cut skin in three cases of mastectomy in which different methods of incision were used - cold blade, the Onemytis plasma device and an Ellman radiosurgical unit - in order to assess the effect of these instruments on the tissues. After positive completion of the first phase, the second phase of the study consisted in the use of the plasma device in different routine surgical procedures. Parameters evaluated included: cutting speed, effectiveness of coagulation and the influence on tissue healing in the postoperative period until removal of the skin sutures and again a week later. Any complications occurring during or after the surgery were recorded. Results - Histological examinations performed in three cases of mastectomy showed the absence of necrosis in incisions made with the scalpel blade, moderate necrosis in those performed with the plasma device and severe necrosis in those made with the radiosurgical device. The clinical study with the plasma device involved 19 dogs and three cats. The dogs were aged between 6 months and 13 years, the cats were 4 to 9 years old. The plasma device was used for skin incision for laparotomy (8 cases), excision of benign skin tumours (4 cases), excision of neoplasms of the oral cavity (3 cases), palatoplasty (2 cases), and cystostomy (5 cases). In all cases, the incisions were performed with appropriate bleeding control and the healing times and modalities were comparable to those expected with a cold knife for skin incisions. In a single case healing was delayed by inflammation secondary to licking. Conclusions - The Onemytis device was shown to be an effective and safe instrument due to low tissue dissipation temperature. In the surgical applications in which it was used it provided cleanly cut surfaces with appropriate bleeding control and without alteration of healing times. The performance of this device in parenchymal visceral surgery needs further study even though in our preliminary experience it was effective and sufficiently delicate when used for cystotomy.