It has instructed its top lawyer to get its famous emblem removed from a picture of pair of underpants used in a sexual impotence campaign.
Hundreds of postcards, featuring a large pair of Y-fronts with a red cross across their centre, have been distributed to British cinemas to highlight the fact that smoking causes male sexual impotence.
But now the charity is demanding that the postcards be destroyed. It says the use of the red cross on the underpants postcard could threaten the lives of people on the battlefield.
A flurry of legal correspondence, between Ash, the anti-smoking lobby group that printed the postcards, and the Red Cross's head of international law has been flying between the two organisations in recent weeks.
The charity claims that its symbol has been violated. It says it has a duty to protect use of the red cross on a white background so that it is instantly recognised by people in trouble and in wars.
"The Red Cross emblem is owned by the Ministry of Defence. It can only be used by the emergency services, the military and the British Red Cross," said a British Red Cross spokesman. "The head of international law is the custodian of the emblem."
But Ash, whose campaign is backed by the British Medical Association, has disputed that the underpants image could be confused by soldiers and civilians seeking aid.
"The Red Cross believes people may die on the battlefield because of this. But the two images are quite distinct," said Clive Bates, director of Ash. "We have pointed out that underpants are quite distinct from a plain white background. For example, the walls in our office are plain white. You would notice the difference if they were decorated with an underpants motif."