Rall's early work on the blood brain barrier led to modern treatment to prevent the spread of leukemia cells to the brain. Much of Rall's work focused on reducing the side effects of
anticancer drugs, which are often toxic in patients when administered in large enough doses to destroy cancer cells. He also researched the effects of prolonged exposure to chemicals in the environments of people in certain occupations. In March 1971, he left the established world of research and clinical treatment at the National Institutes of Health's (NIH) main campus in Bethesda armed with a desire to reach beyond the treatment of chronic disease to seek its underlying causes and, through research, to learn how to prevent such diseases caused by environmental agents. Rall developed the NIEHS Extramural Program to administer an expanding portfolio of PHS grants and awards in environmental health science to researchers at colleges and universities throughout the United States. Rall served as the U.S. coordinator of cooperative environmental health programs between the United States and the U.S.S.R., the United Kingdom, Egypt, Japan, the People's Republic of China, Taiwan, Italy, Finland, and Spain. As a result of his work in attempting to strengthen international scientific cooperation, in 1975 the NIEHS was designated by the World Health Organization (WHO) as a Collaborating Center for Environmental Health Effects. In 1980, Rall played a leading role in an effort to establish the WHO's International Programme on Chemical Safety (IPCS), the goal of which is to provide an internationally evaluated scientific basis for the assessment of the risks to human health and the environment of chemicals. Also, during that NTP-formative era, Rall helped establish the 1978 Public Law that initiated the innovative Report on Carcinogens. He was the author of some 200 scientific publications and was awarded the DHEW Distinguished Service Medal of the PHS and the Arnold J. Lehman Award of the Society of Toxicology. In 1988, Rall received a Merit Award from the Northwestern Alumni Association for his professional accomplishments. ==Recognitions==