Does coca-cola contain horse urine?

No.

Current ingredients are carbonated water, sugar or high fructose corn syrup, caffeine, phosphoric acid, caramel coloring and natural flavorings.

The contents of the natural flavorings include the Coca-Cola formula, which has been secret since it's release to the public. The rumor about it containing horse urine is based around the secrecy of the formula.

Had the formula actually contained horse urine, the Food and Drug Administration (FDA) wouldn't have approved it.

UPDATE:

The answer above is WRONG. The reason why it has been told that pop has horse pee in it is because it does. Phosphoric Acid comes directly from horse pee. Its the only source. Claiming the FDA would protect us is completely naive considering the long running evidence that proves otherwise. They are corrupt and should be considered our enemy.

SODA POP CONTAINS A LOT OF PHOSPHORIC ACID WHICH COMES FROM ONE PLACE.....HORSE PEE. LOOK IT UP.