More than 1,300 people nationwide have been detained on suspicion of making and selling fake medicine, and police have closed more than 140 websites and online pharmacies since late July, authorities said.

A campaign against illegal drug production and sales led to the seizure of 300 million pills and 9 metric tons of fake-medicine ingredients worth a combined 2.2 billion yuan ($362 million), the Ministry of Public Security said on Saturday.

The ministry, which coordinated police in 29 provincial areas, carried out three raids in August, September and October and snared more than 400 groups.

As part of the campaign, police in Henan province broke up a ring alleged to have placed fake-drug ads on the radio and the Internet and used phony medical experts to talk with patients.

More than 40 suspects were detained and more than 21 million pills confiscated.

Online drug sales totaled 1.6 billion yuan last year in China, almost four times the figure for 2011, said Yin Ning, deputy director of the China Food and Drug Administration.

Only 101 websites have been certified to provide services for online drug transactions and information.

Yin said the booming online shopping market provided an opening for fake-medicine distribution.

"Online channels have more variety and make it harder for consumers to trace the products," he said in August.

The Ministry of Public Security said on Saturday that illegal-drug sellers are trying to pitch their products on the Web, using search engines and drug and healthcare websites. Some have even opened online stores or pose as professional medical institutions, sales agents or distribution outlets for drug producers.

Most of the fake medicine seized had been made by mixing starch or deteriorated drug materials with ingredients such as tranquilizers and hallucinogenic drugs, the use of which is a health hazard, authorities said.

Chai Yueting, a professor of e-commerce at Tsinghua University, said the elderly are the most vulnerable to online drug fraud.

"Most consumers who purchase medicine online are urban residents, especially retirees, and they tend to buy medicine for chronic diseases such as hypertension and diabetes," he said. "They yearn for cures, and that leaves them vulnerable to false advertising and illegal drugs."

[email protected]