A Mexican man has reportedly suffered a painful three-day erection after taking a sexual stimulant meant for mating bulls.

According to Peruvian news outlet La Republica, the man took the substance ahead of a planned sexual encounter with a 30-year-old woman.

But, his plan well and truly backfired and he was forced to go to hospital after his erection lasted three days.

“He was admitted to the Specialties 270 hospital of the IMSS of this city (Reynosa),” a statement from doctors said.

An image which has surfaced on social media shows the man laying on a hospital bed surrounded by medical staff.

The man underwent emergency surgery although his condition remains unclear.

The unnamed stimulant is used by farmers to stimulate bulls for insemination. The man reportedly travelled to the city of Veracruz, in the Mexican state of the same name, to buy it.