A DOCTOR has been struck off the medical register permanently for falsifying receipts for bulk medication. The Medical Council heard five separate cases yesterday against Dr Kwok Leong-shon, with a guilty verdict returned in three. The most serious case involved three charges of 'making a false instrument' - relating to Dr Kwok's appearance in the Tsuen Wan Magistrate's Court in May, when she was found guilty of signing drugs receipts for the Wah Ning Dispensary while pretending to be a dispensary representative. Signing those receipts enabled her to obtain 60 boxes of methadone tablets, two bottles of Diazepam, 10 ampoules of Pethidine, 200 boxes of Wellconal tablets and 100 boxes of Physeptone tablets. The chairman of the Medical Council, Professor Rosie Young, described the case as 'extremely serious' and hence Dr Kwok had been removed from the register permanently. 'The profession regards this as a very serious offence. She falsified somebody's authority to supply drugs,' Professor Young said. Dr Kwok, who now lives in Canada, did not attend the Medical Council hearing. She reportedly suffers from psychotic depression. Four other cases involving Dr Kwok and dating back almost five years were also heard yesterday. Two guilty verdicts were returned. She was found guilty by the Medical Council - and by a Tsuen Wan magistrate in March 1992 - of failing to keep a proper register of dangerous drugs - a professional misconduct offence - and was removed from the register for three years. The third guilty verdict related to charges, levelled in January 1990, of falsifying sick-leave certificates and receipts for payment. She was removed from the register for six months. Two other cases - both involving the supply of addictive drugs in 1990 - were dismissed through lack of evidence. The Medical Council had tried repeatedly to hear the earlier cases but action was postponed because of Dr Kwok's health problems.