Police told the firm that tests on three bottles of Coke indicated the drinks were to blame for the poisoning, which had reportedly left one person in a coma on Tuesday.
Coca-Cola Amatil, in charge of group operations in South Korea, said it had been "the subject of an extortion threat affecting Coca-Cola in PET packages". The group has recalled all Coca-Cola, diet Coke and Coke Zero drinks in PET packaging from the country's Kwangju, Hwasoon and Damyang regions.
It is Coca-Cola's second large-scale recall in the southeast Asia region in the last three months. The group withdrew around 2.4m bottles in Japan this May, including flasghip brands Coke and Fanta, amid concerns that iron powder had leaked into drinks at one of its Japanese factories.
The firm said the South Korean recall was a "precautionary measure" taken following police advice, and planned to have Coke back on shelves in PET packages within seven days.
It confirmed police had arrested one suspect, but gave no further details about the nature of the threat.
Coca-Cola is the soft drinks market leader in South Korea, making up half of the country's fizzy drinks market and claiming five, 10 and 20 per cent shares of the juice, water and sports drinks respectively.