Crucifix tattoo could ID mystery man

Police hope a crucifix tattoo will help identify a mystery man being treated at a Brisbane hospital.

The young man was taken to the Princess Alexandra hospital on Sunday night suffering from an undisclosed medical condition.

"He doesn't know who he is. He's unable to tell anyone who he is," a police spokeswoman told AAP.

He was found at a Coorparoo service station about 7pm on Sunday night and remains in hospital in a stable condition.

Police say he has a crucifix tattoo, decorated with Celtic designs, inside his left forearm and scars on the same forearm and left foot.

He's described as Caucasian, about 19 years old and 180cm tall, with fair skin, short dark brown hair and a patchy beard.

He was wearing board shorts and a black t-shirt with green and white writing.

Anyone who may know the man has been urged to call Dutton Park station on 3020 8111 or Crime Stoppers.