Dan was a Robert Wood Johnson Fellow at Johns Hopkins Medical School from 2003-2005, and teaches two undergraduate classes, a research capstone and a seminar class on evaluating evidence based medical decisions. He has been funded by PCORI, NIH, USDA, Foundations and Industry, and is a clinical trialist who has recruited over 2,000 participants for 10 probiotic trials since 2006 and published over 150 articles. As well as being a professor with tenure of Family Medicine at Georgetown University, Dan has a secondary appointment in the undergraduate Department of Human Science, in the School of Health.