 Zheng was director of the State Pharmaceutical Administration from 1994 to 1998, head of the State Drug Administration from 1998 to 2003, and director of the State Food and Drug Administration from 2003 to 2005.In May 2007, Zheng was convicted of taking bribes and dereliction of duty and sentenced to death by a trial court in Beijing.These corrupt practices are believed to have led to 40 deaths in Panama from cough syrup that contained diethylene glycol in place of glycerin.