选择题：56.2 percent of Chinese families buy prescription

56.2 percent of Chinese families buy prescription medicines and store them at home for later use. Of them, about 80 percent throw away medicines that have passed their use by date, a survey reveals.Officials said the government should introduce laws to regulate the collection and disposal of out-of-date medicines. A risk analysis system for medicines should also be established, the experts said.

To study the way people stored medicines and the way medicines were handled after they had passed their used by date, the survey covered more than 1,800 families in 18 cities and counties from Shanghai, Beijing, Guangdong, Shandong, Sichuan and Inner Mongolian Autonomous Region between October and November in 2007. In Shanghai, 56.4 percent of the residents said they threw away out-of-date medicines and 25.5 percent returned them to pharmacies, the highest percentage recorded of all the regions in the survey.About 60 percent of residents knew that out-of-date medicines could be an environmental threat and 75.3 percent were aware of the dangers involved in selling out-of-date medicines to illegal drug dealers.

"The dangers in using out-of-date medicine are more serious than the adverse reactions to drugs. Local drug authorities have begun education campaigns to teach residents to return out-of-date medicines," said the vice director of the Shanghai Clinical Center f