Police have arrested more than 1,900 people suspected of making and selling fake medicine in a series of raids on underground production bases, the Ministry of Public Security said on Sunday.

The nationwide operation, which started on July 25 and involved 18,000 police officers in 31 provincial-level regions, has crushed 24 networks manufacturing counterfeit medical products worth 1.16 billion yuan ($182 million).

Police seized 205 million tablets designed to look like brand-name products for treating hypertension, diabetes, skin diseases and cancer, the ministry said.

Some medicines contained sibutramine, a chemical used to treat obesity that was banned by the State Food and Drug Administration in 2010 due to fears that it increases the risk of cardiovascular problems.

The suspects also put sedative and hallucinogenic chemicals into the tablets to deceive consumers into believing that the fake drugs had an effect.

Police also found bottles of normal saline solution labeled as a rabies vaccine.

The ministry said it has destroyed a large number of production sites and trade channels in the past two years.

However, the crime is "far from being rooted out, as such criminals have come up with new methods", the ministry said in its online statement.

The ministry also said it had found sham promotions of fake products on the Internet, television and magazines during the crackdown.

A ministry spokesperson warned that people should purchase medicines in hospitals and pharmacies who are trusted vendors of genuine products, and advised against buying medicines that do not have approved names and numbers distributed by the SFDA.

"The ministry welcomes reports on the manufacture and sale of fake drugs," read the ministry statement. "We will reward informers 500 to 50,000 yuan if the report is found to be true. We offer ample rewards to those who play an important role in cracking large gangs committing such crimes."

Li Zhongdong, a pharmacist at the Air Force General Hospital in Beijing, said the crime is likely to continue because of "the huge profits" it brings.

"Fake medicines are usually sold to small clinics and small pharmacies," Li said. "There are people who choose to seek medical help from these places, possibly because of lower prices or privacy concerns, which may increase their chances of getting such counterfeit products and their sales."

Li suggested buyers check with the online inquiry system at the SFDA to ensure the medicines they bought are genuine.

The system provides information such as the name and approval number of medicines whose production has been approved by the SFDA.

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