Jing-Mei Chen
Dr. Jing-Mei "Deb" Chen is a fictional medical doctor on the long-running television show ER. The character is played by Ming-Na. Originally, Deb Chen entered the series midway through Season 1 as a medical student. Toward the end of that season, Chen decided she was ill suited to a career in medical practice and would prefer to pursue a career in research. The character was then absent for more than four years, returning in mid-Season 6 as Dr. Jing-Mei Chen. After five years, Dr. Chen departed once again in the 11th season. Ming-Na's addition into the main cast opening credits was in the 10th episode of season 6 and her removal was in the 10th episode of season 11.
Read more about Jing-Mei Chen: Season 1 and Early Life At County, Season 6, Season 7, Season 8, Season 9, Season 10, Season 11 and Departure, Season 15