Aside from the memorably misguided, but mercifully temporary, diversion that was 'New Coke' in 1985, the recipe has barely changed since chemist John Pemberton created it in Atlanta, Georgia in 1886.
Now celebrating its 125th anniversary, what can today's marketers learn from Coca-Cola's record? There is much to praise. Distinctive packaging. Global distribution. Consistent advertising. Soft-drinks rivals talk of the Coke 'machine'.
The machine has sometimes gone off the rails in spectacular fashion, however. Who can forget Dasani? Its UK roll-out must be high on the list of 'how not to launch a new product' case histories.
Indeed, it's fair to say that none of the company's other products has yet managed to match the popularity of its core brand.
A review of campaigns from yesteryear reveals another challenge. Coke has always associated itself with one of America's more appealing traits: optimism. In ad after ad, we are treated to perfect-smiled, healthy youngsters enjoying the good life.
While this may play well in many markets, in the West we have become more cynical and are being encouraged to be more careful about what we eat and drink. In 2008, Coca-Cola had to withdraw a 'myth-busting' newspaper campaign in Australia that flatly denied its product's contribution to rotten teeth and expanding waistlines.
To this end, the company has been pushing energy drinks, juices and teas, as well as no-calorie variant Coke Zero.
Nonetheless, its biggest marketing challenge must surely be maintaining its share of our attention in a media landscape that would have been impossible to imagine in 1886.