Numerous manufactures recommend He-Ne-Lasers for a wide range of applications in medicine and dentistry. An athermal biostimulating mechanism of action is postulated to result in rapid reduction of pain and accelerated wound healing. The efficacy of a commercially available He-Ne-Laser in the treatment of alveolitis, solitary aphthae, ulcers caused by dentures, herpes simplex labialis, marginal periodontopathy and pericoronitis was investigated in 90 cases. Except for a placebo effect no reproducible therapeutic effects could be seen. Nevertheless, there is a high degree of acceptance for laser application by most of patients.