Thomas von Woedtke, Sander Bekeschus, Klaus‐Dieter Weltmann, Kristian Wende

• Plasma‐treated liquids and their medical application have gained momentum in the fields of plasma science in recent years. Most research has been done in the field of cancer treatment. Another new and promising special field of CAP−liquid interaction is hydrogels, which can serve as localized reservoirs for the delivery of long‐lived reactive oxygen and nitrogen species and other active ingredients such as chemotherapeutic drugs. Identifying liquids and hydrogel compositions optimal for plasma treatment, for their reservoir function, and from a regulatory point of view for use in medicine, together with the chemical identification of biologically active molecules and interdependencies to plasma operation parameters, are the fundamental challenges in the field.