HEALTH officials have told Thai men size does not matter after a patient had to have his genitals removed following a botched attempt to enlarge his penis by injecting olive oil into the organ.

The risky and unproven method using the oil - although bees wax, silicone and even paraffin are often also used - is common in Thailand with one Bangkok hospital receiving about 40 patients a month concerned about side-effects.

The 50-year-old man, whose genitals were removed this week after he reported a severe infection, underwent several olive oil injections over a number of years, a spokeswoman for the Bangkok-based Police General Hospital told AFP.

He was diagnosed with cancer prompting the drastic surgery.

"This is the biggest (genital) surgery we have ever done as we found cancer", Sirikul Jiaranaikhajorn said, adding normally the two or three patients they treat each week suffer from infections only but there is no evidence that the procedure causes cancer.

The man had the injections done at a clinic and was accompanied by friends, she added, despite public warnings that such penis enlargement methods are highly risky.

"It only brings bad results - people misunderstand (that it works)," the spokeswoman said, explaining men attempt the procedure after listening to friends.

"A woman will love a man not because of the size," she added.