The shops in Mong Cai, the border town of Quang Ninh Province, and several places in Lang Son Province have advertised their illegal products as "love drugs," which they claim can cure erectile dysfunction and improve sex drive significantly. 
One can step in any of those shops and easily walk out with some pills or lubricants that they are told to take or use at least half an hour before sex. All the names and instructions are in Chinese. 

The lucrative business has reportedly been going on for years. A local official in Mong Cai refused to comment about it. 

Shops selling the so-called "love drugs" near Mong Cai Border Gate in Quang Ninh Province

A vendor named Thuong at a market in Lang Son Province said many of her regular customers come from Hanoi and some now work as her sales reps. 
She said she also has customers from across the country, with deliveries handled by bus services. 
She refused to talk about her suppliers. 
Serious risks
At least two men from Quang Ninh told Thanh Nien that the drugs do not work as expected.
One of them, aged 45, said he was happy with the first pill as his erection lasted more than an hour.
But the next two times, he stayed hard for hours. “I was so scared. I could not even leave home,” he said. 
He said his sex drive has been reduced significantly since.
The other man, 43, said he bought the drugs from Mong Cai. After three bottles, he now suffers from erectile dysfunction.
Doctor Mai Ba Tien Dung, one of the country's top men’s health experts, said his hospital in Ho Chi Minh City usually receives patients who are victims of the so-called love drugs.
Most of them were admitted with penises that had stayed erected for far too long and they needed surgical procedures, he said. 
“Uncontrolled use of those drugs can cause penile fibrosis and increase the risks of heart conditions and blood pressure,” Dung said.