Chelsea have warned they would complain to UEFA should their players suffer racist abuse during Tuesday's game at Napoli.
Members of the Premier League club's squad were reportedly subjected to monkey chants on arriving at the team hotel prior to the UEFA Champions League last 16 first-leg tie.
Blues officials were made aware of the alleged abuse and Chelsea have confirmed they could take any issues to European football's governing body.
A spokesperson said: "Chelsea football club finds any form of discriminatory behaviour totally abhorrent and we believe it has no place in society whatsoever.
"If any members of our team or staff are subjected to racist abuse, we would find that wholly unacceptable and it would be reflected in our conversations with UEFA."
The tie against Napoli is of huge importance to Chelsea, whose under-fire manager, Andre Villas-Boas, is reportedly facing the sack if they are eliminated.
And striker Didier Drogba, who is expected to start in place of the out-of-form Fernando Torres, has issued a rallying call.
The Ivory Coast international said: "I think we are all responsible for the results.
"Chelsea football club is responsible for the results, and I think we all have to play our game. The players have to play their game.
"The good thing in football is that there's always another game to change the bad moment, the difficult moment."