A treatment area marker device and method for using the treatment area marker in setting up a triage facility for patient care. The device and the method may be particularly useful during an emergency or crisis situation. The treatment area marker is an article of manufacture that includes a light source that is capable of generating different colors of light. The bottom end of the treatment area marker has the means for keeping the device in a substantially upright position. The method of triage includes establishing one or more treatment areas, and erecting one or more treatment area markers to identify the treatment area.