Police in Guangdong province have warned the public to beware of fraudulent online ads for medicine that promise to enlarge breasts or enhance sexual performance.

"We advise citizens to improve their awareness to prevent against being conned," Zhang Rui, political commissar of the provincial criminal investigation bureau, said on Thursday. "At the same time, police will spare no efforts to fight this crime."

Four criminal gangs were busted recently for posing as medical experts to sell "powerful aphrodisiacs" and "breast enlargement medicine".

Police detained 220 suspects after raids on 15 locations as part of an ongoing crackdown, as well as seized 335 computers, 442 cellphones, 206 bank cards, nine vehicles and large amounts of fake medicine.

The gangs had together made about 27 million yuan ($3.9 million) by defrauding more than 8,680 people, according to the authorities.

In March, a man who has impotence was conned out of 1,280 yuan after a "medical expert" persuaded him to purchase "aphrodisiacs" over the phone.

A woman also paid 8,296 yuan for "breast enlargement pills" she saw advertised online. She had also been told by a "medical expert" over the phone that her breasts would grow.

Both victims found the medicine was useless.

Police have also detained more than 140 suspects after busting 20 gangs that asked netizens to send congratulatory baskets for various ceremonies, such as the opening of a new store. Raids on 53 locations led to the seizure of 683 bank cards, 271 cellphones, 13 vehicles, 40 computers and 64 cash machines.

Zhang said a series of crackdowns launched to fight robbery, theft and fraud had resulted in police detaining more than 910 suspects in all.