A chemical supplier from Jiangsu province is responsible for producing a fake ingredient used in drugs sold by one of the biggest pharmaceutical firms in Heilongjiang, authorities confirmed yesterday. The supplier - identified as the Jiangsu Taixing Group - has since been shut down by police. At least 11 people fell ill after taking the drugs and four later died. Cao Rongwen, head of the Food and Drug Administration in the Heilongjiang capital Qiqihar , was quoted by Xinhua as saying Qiqihar Pharmaceutical bought the ingredient propylene glycol used in the production of armillarisni A - a medicine for gall bladder inflammation and gastritis - from a chemical company under Taixing. 'And the ingredient turned out to be fake,' Mr Cao said. But he failed to explain why Qiqihar Pharmaceutical did not check the quality of supplies. Jiangsu police have detained a man, Wang Guiping , but a Taixing manager told state television the man was an imposter who forged a company letter claiming to be a representative. The scandal came to light last week when Guangdong authorities said some patients reported serious reactions after using drugs made by Qiqihar Pharmaceutical. The patients have since been taken to hospital. The report prompted Qiqihar authorities to investigate, and the manufacturer was told to suspend production and all its stocks were seized for examination. Xinhua said supplies already delivered to hospitals and pharmacies in Heilongjiang had been recalled. The Xinhua report did not say if any staff from Qiqihar Pharmaceutical would be held responsible. Propylene glycol is a tasteless and colourless oily liquid that is used as a moisturiser in medicines, cosmetics, food and tobacco products. Jiangsu has issued a circular urging all drug companies and pharmacies to stop using propylene glycol supplied by Taixing. Xinhua did not say how much fake chemical manufactured by Taixing had been sold or where.