Water-filtered infrared-A (wIRA) is a special form of heat radiation with high tissue penetration and low thermal load to the skin surface which promotes the healing of acute and chronic wounds both by thermal and thermic as well as by non-thermal and non-thermic effects. Water-filtered infrared-A increases tissue temperature (+ 2.7 °C at a tissue depth of 2 cm), tissue oxygen partial pressure (+ 32 % at a tissue depth of 2 cm) and tissue perfusion. These three factors are decisive for a sufficient supply of tissue with energy and oxygen and consequently also for wound healing and infection defense. Water-filtered infrared-A promotes normal as well as disturbed wound healing by diminishing inflammation and exudation, by promotion of infection defense and regeneration, and by alleviation of pain. These effects have been proven in a total of seven prospective studies (of these six randomized controlled studies) with most of the effects having an evidence level of Ia or Ib. The additional cases of complicated courses of wound healing presented in this article illustrate the proven effects of wIRA. Not only in the 6 presented cases wIRA turned the complicated courses of wound healing for the better and facilitated the healing of the wounds after varying total times of irradiation (in the 6 cases 51-550 h) and after variable times of wound care and mostly after transplantation of split skin grafts. In complicated courses of wound healing wIRA does not replace consultation and, when indicated, treatment by an experienced plastic surgeon and by a surgeon specialized in septic surgery. With these limitations wIRA can be recommended as a valuable complement for the treatment of acute as well as of chronic wounds.