You are allowed to bring a quart-size, zip-lock bag of liquids, aerosols, gels, creams and pastes though the checkpoint in carryon luggage. These combined items need to be less than 3 ounces. More information from the TSA. So the 3-1-1 rule is the TSA's quick reminder: 3 ounces, 1 quart bag and 1 bag per traveler.