Physical plasma is an ionized, quasi-neutral gas. It is often said to be the fourth state of matter. For a long time, plasma was used in medicine exclusively because of its thermal properties for sterilization purposes of surgical equipment and medical supplies, and also to cut and cauterize tissue. The possibility to generate cold plasma in atmospheric conditions marked the beginning of a completely new era in the application of plasma in biomedicine. Plasma medicine is a new interdisciplinary field of science that combines the knowledge of plasma physics to biomedical and clinical sciences. Cold atmospheric plasma emits electromagnetic radiation and it consists out of charged and uncharged particles, among those reactive oxygen and nitrogen species are the most important ones. It is considered that reactive oxygen species cause the most important biological plasma effects, such as inactivation of microorganisms and biofilms. It has been shown in dermatology that cold atmospheric plasma has a healing effect on chronic wounds. First instruments for the application of cold plasma in humans are already commercially available. Cold plasma has a great potential for application in oncology and in dentistry. Numerous studies have yielded very promising results for the application of cold plasma in medicine, but it should be kept in mind that the mechanisms of interaction between plasma and biological tissue are still not fully understood. There is no agreement on the accepted plasma dosages and there are still no standardized instruments for the generation and characterization of plasma. And lastly, for a comprehensive assessment of the potential application of atmospheric plasma in medicine and dentistry we lack more detailed in vivo studies.