Zheng was removed from the post as head of the State Food and Drug Administration (SFDA) on June 22 of 2005 and was involved in a string of bribery cases, reported the China Business Post on Saturday.

Hao Heping, former director of the medical equipment department of the SFDA, was arrested for bribery suspicion merely half a month after Zheng's leave.

Cao Wenzhuang, former director of drug registration department of the SFDA, was under investigation in Jan. of 2006. Both of the two had worked as Zheng's secretary.

Zheng became SFDA director in 1998 when the agency was launched. He had been devoted to promoting a certification system of Good Manufacturing Practice (GMP).

In 2002, China adopted a national standard to replace local standards, which means most of the medicines must be approved by the SFDA before they go into the market.

Those former officials misused the power to take bribes from drug manufacturers, which has led to production of low-quality medicines and caused serious medical accidents.

Xinfu, an antibiotic drug made by a company in east China's Anhui Province, caused at least ten deaths last year. The SFDA banned the use of the product and ordered its recall.

SFDA investigations discovered that the company had failed to observe approved production standards by reducing the sterilization temperature and shortening sterilization time.