A group of Hong Kong doctors visited Guangzhou yesterday to learn from colleagues how to treat babies who developed kidney stones after drinking melamine-tainted milk. Tse Hung-hing, president of the Medical Association, said the group would share what they learned with Hong Kong specialists. 'We have only six suspected cases in Hong Kong. We don't have much experience in handling babies affected by tainted milk, so we came here to learn from doctors in Guangzhou,' he said. Dr Tse and four colleagues were briefed on how doctors at Guangzhou First Municipal People's Hospital treated affected babies. At the peak of the crisis, the hospital treated about 20 babies a day. That number dropped to about 10 cases a day in the past two weeks. Guangzhou doctors treated the babies by giving them soda water to drink regularly, a technique Dr Tse said he would pass on to his Hong Kong colleagues. Meanwhile, the family of a baby who developed kidney stones after drinking tainted milk has tried to sue the dairy giant Sanlu Group. The suit was submitted to Guangzhou Intermediate People's Court, which has only accepted it as a petition and a decision is expected this week.