The Ministry of Health is conducting wide-ranging investigations into the deaths of at least seven patients from contaminated drugs and possible medical blunders. The news has prompted fresh concerns about the standard of medical services on the mainland. Four patients have died at the Sanming No2 Hospital in Fujian province since September 3, Xinhua reported yesterday. It said the deaths were apparently linked to the use of anaesthetics. 'Local health and drugs supervision authorities are investigating the cause of the incidents. Samples of the drugs used in the operations are being tested,' Xinhua quoted a hospital spokesman as saying. A 26-year-old man admitted for acute appendicitis stopped breathing and his heart stopped during an operation on September 3. Doctors revived him but he died 23 days later. Another patient, Zhang Chunmei , 44, suffered similar problems at the hospital while recovering from surgery to remove a cervical tumour. Zhang was also revived but died eight days later, Xinhua said, quoting hospital authorities. A three-year-old died in similar circumstances at the hospital on September 24, while a 29-year-old man died last Friday. Substandard medical services and lax supervision at many mainland hospitals have been sources of public grievances for years, leading to growing calls for restructuring. Meanwhile, the State Food and Drug Administration and the Health Ministry have blamed contamination of a herbal injection for the deaths of three other patients in Yunnan province this month. In a joint statement yesterday, they said tests on samples of the 'ciwujia' Siberian ginseng herbal injection - made by Wandashan Pharmaceutical, based in Heilongjiang - contained bacteria, and an investigation was under way. Six patients in Yunnan showed symptoms such as vomiting after receiving the injections. Three died in hospital on October 6 and the remainder, who were still under observation, were described as stable.