Plasma Medicine is a growing field that is having an impact in several important areas in therapeutic patient care, combining plasma physics, biology, and clinical medicine. Historically, plasmas in medicine were used in electrosurgery for cautery and non-contact hemostasis. Presently, non-thermal plasmas have attained widespread use in medicine due to their effectiveness and compatibility with biological systems. The paper will give a general overview of how low temperature, non-equilibrium, gas plasmas operate, both from physics and biology perspectives. Plasma is commonly described as the fourth state of matter and is typically comprised of charged species, active molecules and atoms, as well as a source of UV and photons. The most active areas of plasma technology applications are in wound treatment; tissue regeneration; inactivation of pathogens, including biofilms; treating skin diseases; and sterilization. There are several means of generating plasmas for use in medical applications, including plasma jets, dielectric barrier discharges, capacitively or inductively coupled discharges, or microplasmas. These systems overcome the former constraints of high vacuum, high power requirements and bulky systems, into systems that use room air and other gases and liquids at low temperature, low power, and hand-held operation at atmospheric pressure. Systems will be discussed using a variety of energy sources: pulsed DC, AC, microwave and radiofrequency, as well as the range of frequency, pulse duration, and gas combinations in an air environment. The ionic clouds and reactive species will be covered in terms of effects on biological systems. Lastly, several commercial products will be overviewed in light of the technology utilized, health care problems being solved, and clinical trial results.