A United Airlines plane from New York to San Francisco was diverted to Chicago on Tuesday after a passenger reported suspicious materials.

A bomb unit was alerted after United's flight 27 with 74 people on board was diverted to Chicago's O'Hare Airport, but police investigating the complaint said the items turned out to be vials of a harmless herbal extract.

"The suspicious material turned out to be a passenger with a couple of vials with an herbal liquid. They spoke to the passenger. There are no arrests," police spokeswoman Laura Kubiak said.

Airline spokesman Jeff Green said the crew could not identify the materials and acted appropriately by confiscating the vials and diverting to O'Hare.

"We're told by authorities the materials were lotions and the passenger is a healer," Green said.