The standard airline toiletry rule, as enforced by the TSA and most international aviation authorities in 2026, is known as the 3-1-1 Rule. This mandates that all liquids, gels, and aerosols in your carry-on luggage must be in containers of 3.4 ounces (100 milliliters) or less. All of these containers must fit comfortably inside a single one-quart-size (liter-size) clear, sealable plastic bag. Each passenger is limited to one such bag. Common travel items that must follow this rule include toothpaste, shampoo, conditioner, lotion, and liquid foundation. There are three major exceptions to this rule: medically necessary liquids (such as insulin or liquid prescriptions), baby formula/breast milk, and baby food. These items can be in larger quantities but must be declared to the security officer for separate manual screening. If you are a member of TSA PreCheck, you generally do not have to remove your 3-1-1 bag from your luggage during the screening process, making the journey much faster. Any toiletries larger than the 3.4-ounce limit must be placed in your checked baggage or they will be confiscated at the security checkpoint.