Police are appealing people and organisations in Northallerton to come forward if they have received an unexpected cash donation in an envelope.
Officers were contacted today after three such donations were handed to them for safe-keeping.
A North Yorkshire Police spokesperson said; "At this stage there is no suggestion of anything suspicious, but there is a possibility that more envelopes have been handed out in the area.
"A local woman aged in her 50s is receiving medical support while enquiries continue."
People who have received an unexpected donation are asked to make arrangements to hand the items to the reception at Northallerton Police Station at Alverton Court, Crosby Road, Northallerton, DL6 1BF.