Ashley Randall, 31, ran off from ambulance staff on Bloxwich High Street around 11am on Thursday, West Midlands Police said.
The force has now asked for the public's help tracking him down, saying they are concerned for his welfare.
Mr Randall is described as 5ft 8ins tall, slim and with mousy brown hair, wearing grey bottoms and black trainers and bare chested.
A spokesman for West Midlands Police said: "Have you seen Ashley Randall?
"We are concerned for his welfare as the 31-year-old was being treated by the ambulance service but ran off.
"He was last seen on Bloxwich High Street around 11am today (16 Sep) wearing grey bottoms, black trainers and was bare chested.
"Ashley is 5ft 8ins and described as slim with mousy brown hair.
"If you have seen Ashley or have information that could help us find him, 101 or Live Chat quoting log 1317 of 16/09/21."