Hong Kong businessmen and travellers are smuggling Viagra into the mainland, where some sell it to friends for as much as four times the price in the SAR. Regulars at Guangzhou's trendiest bars and discos said their Hong Kong friends were sneaking the anti-impotence pills through immigration checkpoints. They either gave them to friends as gifts or sold them. 'Most people bring it back for friends, but some people sell it on a small scale for $200 to $300 a pill,' said Kwan Ying, a 28-year-old man visiting a popular club. 'A friend of mine tried to sell it to me for $400. I didn't buy it because I don't need it.' In Hong Kong, a pharmacist said Viagra had become a popular gift apart from wine and cigarettes for mainlanders. The pharmacist, who runs a dispensary in Central, said he had many customers asking for Viagra to take as gifts to friends and mainland business partners. 'Before the drug was registered here, they kept asking me if they could get some supplies,' he said. 'They said their business partners and also officials on the mainland were crazy for it.' He said the customers told him that giving out Viagra had become fashionable. 'They think if they can get some they will have a better chance for business.' The drug became available for purchase on prescription in the SAR last month. However, sales are not permitted on the mainland, where clinical trials have yet to be completed. Almost as soon as the pills hit the market in Hong Kong, they began surfacing in some mainland nightclubs. Customers said they had been approached by strangers asking if they were interested in trying the drug. A 30-year-old man said: 'I know there are a lot of the pills coming from Hong Kong. The prices are high.' Medical experts worry about widespread misuse. Professor Zhu Jichuan, chief of the urology department at the People's Hospital of Beijing Medical University, said: 'This drug should only be available on prescription. I'm against it being sold in nightclubs. That can be very dangerous.'