China's drug regulator ordered a nationwide recall of a hemorrhoid medicine Wednesday because of concerns it may cause liver problems in the latest drug problem to hit the country.

The State Food and Drug Administration said in a statement on its Web site that it had ordered Vital Pharmaceutical Holdings Ltd., based in Sichuan province, to stop producing Zhixue capsules and begin a nationwide recall after 21 people around the country developed liver problems after taking the medicine in recent months.

"An obvious connection can be found between the hemorrhoid medicine and the liver damage after case analysis, but the cause of the adverse reactions remains unknown," the statement said.

China's pharmaceutical industry is highly lucrative but poorly regulated, resulting in some companies using fake or substandard ingredients. In recent years, a string of fatalities blamed on counterfeit or shoddily made medications has been reported.

Several herbal medicines have been recalled in recent months because of suspicions they have caused deaths, according to the official Xinhua News Agency.

The recalls come as China tries to reassure consumers over a scandal involving the spread of the industrial chemical melamine into the food chain, the latest incident to mar its already troubled product safety record.