Health authorities Thursday warned that many “natural remedies” for erectile dysfunction that are currently being sold illegally online contain sildenafil, a medication that can be purchased only with a doctor’s prescription.

An overdose of the drug, which is most commonly sold as Viagra, can lead to serious health problems including a heart attack. The authorities strongly advised the public to consult a doctor before purchasing any medical or non-medical remedies for erectile dysfunction.

Among 22 “natural remedies” currently being sold online that were selected for an investigation by the Ministry of Food and Drug Safety, 19 illegally contained sildenafil, a medication that is used to treat pulmonary hypertension and erectile dysfunction. The ministry also discovered two illegal and fake “Viagra” drugs for sale online, which had more than 250 milligrams of sildenafil per tablet ― 10 times more than what is considered safe and appropriate.

“Drugs in Korea cannot be sold and purchased online according to the law,” said an official from the ministry. “Those who have already purchased the drug online must stop taking them immediately.”

In order to minimize possible damage and block citizens’ access to the illegal products online, the drug ministry filed a request with the Korea Communications Standards Commission to shut down all websites involved with illegal drug sales.

Side effects of sildenafil include headaches, impaired vision, heart attack and sudden hearing loss.

By Claire Lee (dyc@heraldcorp.com)