Coca-Cola staff in Invercargill are dressing in plain clothes and under protection of a security firm after receiving threats from a man who says the beverage killed his wife.
The man, name unknown, says his wife drank 10 litres of Coke a day, and ate very little.
Coca-Cola Amatil New Zealand managing director George Adams said a "very irate" man had threatened to kill his staff, so they were now avoiding wearing Coca-Cola uniforms or driving branded cars.
He had seen the results of an inquest into the woman's death early last year, which showed she was deficient in nutrients and minerals, like potassium.
He said the claim Coke killed her was "patently untrue".
Police have spoken to the man accused of making the threats.