scopolamine

When they meet, the man is handed a drink spiked with a substance such as scopolamine, which can cause people to fall unconscious and block their memories.

Carlos Calle, the former director of the city's tourism observatory, said it's common for criminals to drug tourists with scopolamine, an odourless substance known as "Devil's Breath".

Rapid-acting antidepressants, including ketamine, scopolamine and psilocybin, have been found to have immediate and lasting positive effects on mood in patients with major depressive disorder but how these effects arise is unknown.

Other horses in the area also tested positive for the prohibited substance scopolamine, which is not considered a traditional performance enhancer.

Scientists began experimenting with a combination of scopolamine and morphine at the turn of the 20th century.