CREVE COUER, MO (KTVI)-- Demonstrators and police face off at Monsanto headquarters in Creve Couer.
Some of them were arrested.
Protestors think genetically modified food is dangerous and want Monsanto to support mandatory labeling.
Monsanto scientists say genetically modified food has been around for more than 20 years and is proven safe.
Company shareholders voted thumbs down on supporting mandatory labeling.