Senior research investigator Searle Laboratory, Skokie, Illinois, 1968-1972. Section head Abbott Laboratory, North Chicago, Illinois, 1972-1976. Resident internal medicine Chicago Medical School, North Chicago, 1976-1977, St. Joseph Hospital, Chicago, 1977-1978.
Fellow in hematology, oncology Rush-Presbyterian St. Luke and Cook County Hospitals, 1978-1981. President L&L Clinic, Rockville, Maryland, 1982-1985. Medical director The Lee Clinic, Villanova, Pennsylvania, 1985-1993, attending physician Jefferson Park Hospital, Philadelphia, 1985-1991, Thomas Jefferson University Hospital, Philadelphia, since 1991.
Medical director Liberty Medical Center, Philadelphia, since 1993. Attending internist, hematologist, oncologist Shady Grove Adventist Hospital, Rockville, Maryland, 1982-1985, Leland Hospital, Riverdale, Maryland, 1984-1985. Postgraduate pharmacologist University of California at Los Angeles, 1967-1968.
Clinical consultant Spruce Medical Center, Philadelphia, 1985-1991. Consultant physician Embreeville Center, Coatesville, Pennsylvania, 1991-1992. Clinical consultant Triservice Clinic, Bethesda, Maryland, since 1986.
Specialist Bethesda Research Laboratory, Rockville, 1981-1982. Attending hematologist District of Columbia General Hospital, Washington, 1981-1982. Member medical faculty Georgetown University, Washington, 1981-1982.
Staff physician Covenant House Health Services, since 1994.
Member American Society Pharmacology and Experimental Biology, Federation American Societies for Experimental Biology, American Chemical Society (medicinal chemistry division), New York Academy of Sciences, Formosan Medical Association, Chinese Health and Medical Association, American Center for Chinese Medical Studies, National Taiwan University Medical School Overseas Alumni Association (president 1969-1971), Hakka Association Washington Metropolitan Area (president 1983-1984), National Reconstruction Seminar of Taiwan. (District of Columbia chapter), National Taiwan University Alumni Association in Greater Philadelphia Area (president 1986-1988).