When avocado is mashed and turns dark is it still edible?

Yes, mashed avocado that has turned dark is still edible, although it may not look appealing. The browning is caused by oxidation, which occurs when the flesh is exposed to air. To minimize browning, you can add lemon or lime juice, which contains citric acid that helps preserve its color. However, if there are any off smells or signs of mold, it's best to discard it.