Aggarwal's work is focused in the fields of gastroenterology and hepatology with special emphasis on viral hepatitis, in particular Hepatitis E and Hepatitis B, on which he has conducted research from epidemiologic, clinical and laboratory perspectives.[3] He has also contributed to the areas of health economics and immunization.[7] His studies have been documented by way of a number of articles[8][9][note 1] and ResearchGate, an online repository of scientific articles has listed several of them.[10] Besides, He has mentored several research scholars in their doctoral studies.[11]
Aggarwal has been the principal investigator of several projects funded by various Indian funding agencies. Biomedical Informatics Centers of ICMR was another project managed by him, on sponsorship from the Indian Council of Medical Research.[12] He sits in the Panel of experts on Gastroenterology of the Ministry of Health and Family Welfare[13] as well as the Scientific and Technical Advisory Committee on Viral Hepatitis of the World Health Organization and has conducted several workshops which included the V. S.R. Naik Memorial Workshop on Computers and Informatics in Medicine held in 2008[14] and the Workshop on Scientific Writing of the Indian Council of Medical Research held in September 2010.[15] He was a member of the experts' panel of SAGE Working Group on Hepatitis E from October 2013 to December 2014[16] and has also been associated with scientific journals as an editor.[3]