China's drug administration on Wednesday warned consumers not to purchase illegally imported cancer drugs online, as most of the drugs are fake.

A circular issued by China Food and Drug Administration (CFDA) said the authority found that "Iressa" and some other cancer drugs that were claimed to be imported from India were being sold online at a price about one-tenth that of legal drugs of the same kind.

The administration investigated these cases and found that the drugs were not licensed by the CFDA and most of these products were fake drugs produced in China at illegal sites, the circular said.

There are also drugs that were purchased by unqualified individuals from inauthentic sources abroad and illegally imported to China, it added.

The CFDA warned consumers not to buy these fake drugs and noted that the sale of all kinds of cancer drugs requires a doctor's prescription and selling prescription drugs online is not allowed.

"Iressa," also known as Gefitinib, is a drug used to treat breast, lung and other cancers.