Background: Patients suffering from advanced head and neck tumors frequently suffer from superinfected chronic wounds caused by necrotic tis- sue due to progressive tumor growth, weak systemic and local immunological response and various accompanying illnesses. Due to strong wound vulner- ability, local antiseptic wound care of microbial contaminated tumor areas is frequently complicated by bleeding, pain and patient dissatisfaction. As Cold Atmospheric Plasma (CAP) has been proven to be anti-microbial and anti- cancerous, CAP could occupy an important role in palliative cancer care. Material and methods: After a curably intended surgical cancer treatment of a well-differentiated squamous cell carcinoma of the left cheek at the beginning of 2015, the 51-year-old patient noticed a rapidly progressive swelling on the left neck in June. CT scan indicated a large contrast enhancing mass, which was suspected to be tumor recurrence. Operative findings revealed inoperability due to infiltrating the vascular wall of the external carotid. After a palliative intended combined radio- chemotherapy, the tumor was characterized by progressive growth with exulceration. Due to the vulnerability of the extended bacterially con- taminated wound and the underlying carotid artery, wound care was difficult. Since October, a supportive palliative cancer treatment using CAP has been started with the patients' written consent. The exulcerative tumor growth region received treatment with the kINPenMED (Neoplas GmbH, Greifswald, Germany) for near 5 minutes in a meandering manner. Plasma treatment was continued to be performed every 3 days. Wound care was implemented in conjunction with an antiseptic wound dressing. Results: The superinfected necrotic tumor areas appeared to be clean of cell detritus and bacteria. Microbiological examination revealed a reduc- tion of bacterial colonization which led to decrease of wound odour, too. Due to the decrease of inflammation, vulnerability and wound algesia have been reduced significantly. Upon CAP therapy a partial tumor response with tumor mass reduction were observed. The ulcerated tumor area has been reduced to one-quarter of its original size. The underlying carotid artery is still intact and ultrasound investigation revealed a regular blood flow. Histological examinations revealed an increased amount of apoptotic tumor cells and a local increase of immune defense. Further- more, a desmoplastic reaction of the conjunctive tissue represented by a higher proliferation rate of fibroblasts could be depicted. No plasma relevant systemic side effects have occurred. Conclusion: By a sufficient reduction of bacterial colonization,decrease of inflammation, wound vulnerability and algesia, CAP constitutes an innovative and valuable treatment option in palliative cancer care. Local tumor mass reduction is an unexpected and promising response during CAP treatment and has to be further examined.