Why would a vampire have yellow eyes?

Because they feed on so much blood, and a breakdown product of hemoglobin is bilirubin, which produces jaundice, all vampires soon develop jaundice and are actually very sickly. read more

In the"Twilight Saga" mythos, vampires with red eyes indicate that the vampire has eaten human blood, which is why James' coven has red eyes as well as the Volturi. If a vampire has only had animal blood ("vegetarianism" as the Cullens say), like Edward's family, their eyes would be golden. read more

Best Answer: The cullen's have yellow eyes because they are 'vegetarians' meaning they only drink animal blood. They do not want to be murderers, so this is why they do this. The other vampire's have red eyes because they drink human blood. read more

The twilight vampires have red eye’s because they drink human blood, some vampires like the Cullen's have yellow eyes because they drink animal blood, the brightness of the colors of their eyes depends on when they last fed. read more