TSA Liquid Rules, Medication Policies, and Other Carry-On Regulations Explained

The 3-1-1 rule: how it works

The TSA's carry-on liquid policy is known as the 3-1-1 rule. Each liquid, gel, cream, paste, or aerosol container must hold 3.4 ounces (100 milliliters) or less. All containers must fit inside one clear, quart-sized resealable bag, and each traveler may bring one such bag. That bag goes in the bin by itself during X-ray screening.

The rule applies to a wide range of products: shampoo, conditioner, toothpaste, sunscreen, mouthwash, contact lens solution, and similar items. If a container holds more than 3.4 oz, it cannot go in your carry-on even if it is only partially full. Pack it in checked luggage or transfer the contents into a smaller travel bottle before you leave.

Travelers enrolled in TSA PreCheck typically do not need to remove their quart bag from their carry-on at the checkpoint, though the same size limits still apply.

Medication and medical supplies

Prescription and over-the-counter medications in liquid form are exempt from the 3-1-1 limit. You may carry medically necessary liquids in quantities greater than 3.4 oz, but you must declare them to the officer at the checkpoint before screening. TSA may need to open and test these items.

Solid medications (pills, tablets, capsules) have no volume limit. They can stay in original labeled containers or a pill organizer; neither format is required by TSA, though labeled containers can help if an officer has questions.

Insulin, syringes, and other diabetes-related supplies are permitted. Inform the officer that you are carrying them. Ice packs or gel packs used to keep medication cool are also allowed in any quantity, though they may receive additional screening if they are partially frozen or slushy.

Medical devices such as CPAP machines, nebulizers, and bone stimulators are allowed in the cabin. Remove them from their cases for X-ray screening. TSA's website lists specific guidance for individual devices if you want to confirm in advance.

Food, baby items, and other exempt liquids

Baby formula, breast milk, and toddler juice are allowed in quantities that exceed 3.4 oz and do not need to fit in the quart bag. Inform the officer at the checkpoint, and be prepared for additional screening. The same applies to liquid or puree baby food.

Solid food in carry-on bags is generally permitted, but liquid or gel-based foods (yogurt, hummus, peanut butter, jam, soup) are subject to the 3-1-1 rule because TSA classifies them as gels or liquids. Whole fruit, sandwiches, and dry snacks travel with no restriction. If you are uncertain about a specific food item, the TSA "What Can I Bring?" tool on TSA.gov lets you look it up by name.

Electronics, sharp objects, and other common restrictions

Laptops and tablets larger than a standard paperback book (roughly 7 inches or more) must be removed from your bag and placed flat in a separate bin for X-ray screening unless you have TSA PreCheck. Smaller tablets, e-readers, and phones can stay in your bag.

Lithium-ion batteries (including spare laptop and phone batteries and power banks) must travel in carry-on bags, not checked luggage, because of fire risk in the cargo hold.

Sharp items follow specific rules. Scissors with blades shorter than 4 inches are allowed; longer blades go in checked luggage. Disposable razors and cartridge razors are permitted. Straight razors and safety razor blades (without the handle) are not. Small pocketknives with blades under 2.36 inches (6 cm) are technically on the TSA prohibited list and may not be carried on.

For the full list of prohibited items and edge cases, check our airport reference guide for additional context on navigating security and terminals. If you want to weigh whether certain items make carry-on travel practical for your trip, this packing trade-off guide covers the decision in detail.