This 5-cent stamp honoring the Mayo Brothers, who founded the Mayo Foundation for Medical Education and Research in affiliation with the University of Minnesota at Rochester. It was first placed on sale through the Rochester, Minnesota, post office on September 11, 1964. The stamp was inspired by statues by James Earle Fraser of Dr. William J. Mayo (1861-1939) and his brother Dr. Charles H. Mayo (1865-1939). It was printed in green, the medicine's symbolic color. Another symbol of healing, the staff of Aesculapius, appears in the lower left of the stamp.
This stamp was printed by the rotary process and issued in panes of fifty stamps each. An initial printing of 120 million stamps was authorized.
Postal Bulletin (August 20, 1964).