Authorities say several dozen people were treated for alcohol-related illnesses at a weekend Keith Urban concert in Massachusetts.

Ambulances from five surrounding communities responded to the Saturday night concert at the Xfinity Center in Mansfield, about 50km south of Boston, police and fire officials say.

At least 46 people were treated and 22 were taken to local hospitals.

Police say more than 50 people were taken into protective custody at the concert, and some could face charges.

Officials say about 18,000 country music fans attended the concert at the outside venue.