The bottles have been going missing from outside Danes Dykes Surgery on Scalby Road in Scarborough for more than a year.
North Yorkshire Police said: "Can you help with our investigation after a spate of milk thefts spanning over a year from outside Danes Dyke Doctors surgery on Scalby Road in Scarborough? We've issued CCTV of a man we'd like to speak to as we believe he may have info that will help the investigation.
"If you can help, please contact us on 101, option 2, and ask for Dave Brant. Or email [email protected] If you wish to remain anonymous, you can pass information to Crimestoppers on 0800 555 111. Please quote ref 12220069796 when providing details."