The Russian Football Union (RFU) is warning players against drinking “exotic tea” or smoking shisha pipes as it tries to avoid any doping cases ahead of its home World Cup.

In a guide to help players avoid failing drug tests by accident, the RFU says players should be wary of accidentally consuming banned substances.

It recommends players always read the label on exercise supplements and check online whether they're contaminated with banned products.

The RFU also advises players “not to consume exotic tea,” to avoid smoking shisha, and to be wary of possibly contaminated meat from China or South America.

It wasn't immediately clear what prompted the tea warning.

An Algerian player was banned after a 2015 positive test for cocaine he said he accidentally consumed via a friend's shisha pipe.