As long as a bottle of Gatorade has been sealed properly, there should be no ill effects of drinking it past the expiration date on the bottle, according to EatByDate. There may be a slight difference in taste and color, but there are no health reasons not to drink it.
The drink-by date on bottles of Gatorade are not necessarily expiration dates. Instead, they are the last date the manufacturer guarantees freshness and flavor. To ensure that Gatorade is good to drink past the date on the bottle, store it in a cool, dark place, and ensure that the integrity of the seal is not compromised.