The Hospital Authority is to investigate a drug manufacturer after the recall of 4,000 bottles of liquid paracetamol - most of which are believed to have been drunk by sick children. The medicine, used to treat fever in youngsters, had a defect that turned it to jelly. Only 16 of the 4,000 bottles of paracetamol, made locally by Vida Laboratories, had been collected yesterday. It is believed most of the rest were consumed, an authority spokeswoman said. The authority said it had secured another supplier. 'We are not only looking at this medicine but also the entire production process of the manufacturer,' chief pharmacist Lee Pak-wai said. 'If there's a problem found in the production, we may consider not dealing with them again.' Other medicines supplied by Vida, based in Kwai Hing, are being used by public hospitals but account for only a small proportion of what the authority dispenses, Mr Lee said. The bottles of dubious paracetamol oral suspension had been dispensed by 24 public hospitals since September. Initial findings showed the defect was caused by a failure of the laboratories to mix the medicine syrup correctly. The problem was uncovered when liquid in several bottles at public hospitals' dispensaries settled and turned to jelly. Tests by Vida showed the batch would not cause harm even if taken in jelly form, according to the authority. But doctors said people with kidney or liver diseases might develop minor gastric and intestinal problems. Vida is expected to give a detailed account of the incident today.