One in four British doctors say they have treated patients for side effects produced by drugs purchased from rogue online pharmacies, such as no-prescription pharmacies, the U.K.’s Telegraph reported last week.

Physicians reported seeing patients who had experienced problems after buying a wide variety of drugs online, including medication for anxiety, insomnia and weight loss. Doctors also said they had seen patients who had side effects after buying fraudulent versions of Viagra or other sexual impotence medications.

More than 400 physicians responded to the survey by Britain’s GP Magazine.

Concluded Dr. Bill Beeby, prescribing lead for the British Medical Association’s GPs committee:

When it comes to buying drugs on the internet, it is a minefield. People just don’t know what they’d be getting.

Don’t step into the minefield of no-prescription pharmacies. It’s not worth the risk.

By using freely, you can be sure the medications you order come from properly licensed online pharmacies — so you can save while also staying safe.