SHANGHAI -- China is fertile ground for startups. Every day, some 12,000 new businesses are created there. Having the world's largest population means plenty of chances to test new products and services, and the country's often freewheeling business environment rewards innovation. That innovation was on display recently in a Shanghai drugstore, where a customer was taking his blood pressure and blood sugar readings with in-store equipment. An employee asked him for his phone number and other personal information and then fed the data into a computer. On the screen, the customer's readings from earlier visits, as well as his shopping history there, popped up. "Your blood pressure has been rising recently," the employee told him, then recommended specific medicines based on the latest readings. This personalized service was made possible by Shanghai CareLinker Medical Technology. The company has developed an online system that links terminals at some 5,000 drugstores across China. The central server stores health data collected from customers via the terminals at drugstores. The information is updated with each visit and can be viewed from any terminal. Liu Kai, a former doctor, launched the business in October 2014 with an ex-Samsung engineer and other partners. He was drawn to the idea of tailoring treatments to the individual. "Two people with similar symptoms might receive the same medicine," Liu said. By having access to more data on each person, Liu believes, a more accurate picture of their health will emerge, meaning a better chance to treat them with the medicine best-suited to their needs. The service has quickly spread across Shanghai and other cities. Today, it has more than 1.6 million registered users. A big part of the reason the system has caught on so quickly is that Chinese drugstores do not operate under regulations as strict as those seen in, say, Japan and the U.S., where drugstores cannot sell certain types of medicine without a prescription written by a doctor.