An American man is suing the fast-food restaurant chain McDonald's for $US1.5 million because it did not give him enough napkins.

Webster Lucas claims he is suffering "undue mental anguish" and cannot face work after the trauma of his experience.

The man bought a Big Mac at an outlet in California but was refused extra napkins by a manager, who said he had already been given some.

Mr. Lucas - who is African-American - claims things then turned racist with the manager.

It is reported he later e-mailed a complaint and was offered free burgers in return.