The leaflet reads "You may not want to enlarge only muscles...", advertising a penis enlargement service in Bangkok. (File photo)

The Department of Health Service Support has warned men of the perils of unapproved injections intended to enlarge their penis, saying it could lead to severe infection and even cancer.

Deputy director-general, Arkhom Praditsuwan said on Tuesday it was very common for Thai men to get penis injections in the hope of impressing women, although the department had issued repeated warnings against the risks.

Illegal clinics that give the injections use substances that are not approved by doctors, such as olive oil, vegetable and industrial-grade silicone, Dr Arkhom said.

He said injecting these substances into a penis cannot enlarge its size, but can cause infection, swelling and lack of elasticity, resulting in difficulty urinating and having sex.

Those who get the injections also risk contracting deadly viruses such as HIV and hepatitis if the equipment is contaminated, he added.

Severe and chronic infections as a result of unauthorised injections can require amputation and cause cancer.

Providers of the unauthorised injections face a jail term of up to three years and/or fine of up to 30,000 baht for violating the Medical Profession Act.

They could also be jailed for up to five years and/or fined up to 100,000 baht for operating an illegal clinic, in violation of the Health Facility Act, said Dr Arkhom.