Agent Orange Act of 1991 establishes provisions for the National Academy of Sciences to analyze and summarize scientific evidence regarding presumptive military service exposure to defoliants, dioxins, and herbicides, better known as Agent Orange, during the Vietnam War era. The United States Statute endorses an observation of human medical conditions directly related to non-Hodgkin lymphoma, soft-tissue sarcoma, chloracne, and consistent acneform diseases for military personnel who served in the overseas Vietnamese region. The Act of Congress ratifies a medical research compilation of voluntarily contributed blood and tissue samples provided by Vietnam-era veterans serving in Southeast Asia between 1961 and 1975.