It's difficult to imagine a sector that could register a sales increase of more than three times in just one year, with insiders predicting its growth momentum to continue over the next few years or even longer.

But that is the tale of online drug sales in China.

Sales in the sector jumped to 1.65 billion yuan ($270 million) in 2012 from 440 million yuan a year earlier, according to the China E-business Research Center. The market research firm also found that web users viewed medical service and health websites twice a day on average, and there were more than 1,000 online drug retailers in 2012.