TSA carry-on liquid rules use both an item’s purpose and its container size. Ordinary toiletries follow the 3-1-1 rule. Medically necessary liquids, infant and child nourishment, and some cooling accessories follow separate screening procedures.
At U.S. Transportation Security Administration checkpoints, classify items before measuring them. Separate exception items before you reach the checkpoint. TSA approval does not decide airline, destination-entry, medical, or Federal Aviation Administration hazardous-material requirements.
Classify Liquids Before Measuring
Use four screening paths
Do not put every product into a smaller bottle first. Identify the correct path:
- Possible dangerous good: If a product contains fuel, pressurized gas, flammable or corrosive material, batteries, or another hazardous component, it may require FAA review as well as TSA screening.
- Infant or child nourishment: This category includes formula, breast milk, toddler drinks, baby food, toddler food, and related cooling accessories, all of which have separate screening procedures.
- Medically necessary item: For liquid medication, medically necessary creams, and related cooling accessories, screening can occur outside the ordinary quart bag in reasonable quantities.
- Ordinary liquid, aerosol, gel, cream, or paste: Toiletries, cosmetics, and similar products follow the 3-1-1 rule.
For uncertain items, search the TSA What Can I Bring list. Use the product’s actual purpose and contents, not labels such as “essential,” “travel size,” or “natural.” TSA instructions can change, so check the current listing near departure.
The product’s purpose matters even when products look alike. A gel pack for cooling medication may be handled differently from one for a picnic. A baby-food pouch is not treated like an ordinary snack spread. A pressurized toiletry may raise a separate hazardous-material question even if it is an ordinary aerosol.
TSA officers have final screening authority. A normally permitted item may need more screening or may be refused if it triggers an alarm, looks altered or tampered with, or raises another security concern. Correct packing helps but does not guarantee admission at the checkpoint.
Pack Ordinary Liquids Correctly
Use the 3-1-1 bag
For ordinary carry-on liquids, aerosols, gels, creams, and pastes, the TSA Travel Tips fact sheet gives these 3-1-1 rules:
- Each container must hold 3.4 ounces or 100 milliliters or less.
- Containers must fit in one clear, quart-sized, zip-top bag.
- Each passenger may carry one bag.
Examples include shampoo, conditioner, lotion, toothpaste, liquid foundation, perfume, mouthwash, and aerosol deodorant. The amount left inside does not change the rule. A half-full bottle labeled 6 ounces is still oversized.
Keep the quart bag where you can remove it without unpacking other compartments. Put only ordinary products in it. Keep medical and nourishment items that qualify for separate screening outside the bag so their purpose is clear.
The 3-1-1 rule does not apply to every substance that is liquid. Knowing the difference helps you avoid two errors: checking an item that may qualify for separate carry-on screening, or assuming a medical label removes all screening requirements.
Decide when to check an item
A checked bag can work for oversized ordinary shampoo, lotion, beverages, or liquid food. It is not a solution for every item. Before checking something, confirm that checked baggage permits it and that it does not raise a separate FAA dangerous-goods issue.
Checked baggage does not settle airline or destination rules. Airlines may set conditions beyond TSA screening rules. Destination authorities may restrict food, agricultural products, alcohol, or other goods at entry.
For items involving fuel, pressure, flammable ingredients, corrosives, or batteries, review FAA PackSafe. FAA rules address whether a dangerous good may travel by air and where it may be packed. TSA rules address checkpoint security. One does not replace the other.
Avoid the oversized-liquid shortcut
“Anything over 3.4 ounces must be checked” is too broad. It is a useful default for ordinary liquids, aerosols, gels, creams, and pastes. It does not apply to medically necessary liquids or eligible infant and child nourishment.
The opposite assumption is also wrong. Medical and nourishment exceptions are not unlimited. TSA uses a reasonable-quantity standard and expects travelers to declare qualifying items for separate screening. Officers may inspect containers, use another screening method, or address a security concern unrelated to the item’s purpose.
Separate Medical And Child Items
Carry medical liquids in reasonable quantities
Medically necessary liquids, medications, and creams may exceed 3.4 ounces or 100 milliliters in carry-on baggage when the amount is reasonable for the trip. They do not need to fit in the regular quart-sized bag. The TSA medical screening guidance says to declare them and present them for separate screening.
Tell the TSA officer about medically necessary liquids before screening begins. Keep them accessible, separate from ordinary toiletries, and ready for inspection. Keeping related supplies together can help show their medical purpose.
“Reasonable quantity” is not one fixed number. Carry an amount connected to the trip. Expect questions or more inspection if the quantity, packaging, or contents need clarification.
Checkpoint guidance does not replace medical advice or a complete medication travel plan. Storage, prescriptions, devices, clinical documentation, airline procedures, and cross-border medication questions need separate planning. The Flying With Medication collection covers those broader issues.
Pack formula and baby food separately
Formula, breast milk, toddler drinks, and baby or toddler food, including purée pouches, may use a separate screening exception when they exceed 3.4 ounces or 100 milliliters. The TSA complete item list says these items do not need to fit in the quart-sized bag.
Tell the officer about them when screening starts and remove them from the carry-on for separate inspection. TSA may test containers or use another screening method. Keep nourishment supplies together and use packaging that is easy to present.
TSA also says the infant or child does not have to travel with the passenger carrying breast milk, formula, or related supplies. This can help a parent, caregiver, or another traveler transporting nourishment for a child.
Keep this category separate from ordinary liquid food. A pouch made for an infant or toddler may qualify for the nourishment path. A similar pouch made for an adult may be treated as ordinary liquid or gel food. Check TSA’s item search when the purpose is unclear.
Handle cooling accessories by purpose
For cooling accessories, ask two questions: What are they cooling, and what state are they in at screening?
An ordinary frozen liquid item or gel pack generally must be frozen solid. If it is partly melted, slushy, or contains liquid, it must meet regular 3-1-1 requirements. A partly thawed picnic cooler pack may therefore be difficult to take through the checkpoint.
Medical cooling accessories follow a separate path. TSA guidance covers ice packs, frozen gel packs, and similar accessories used for medically necessary liquids. Medically necessary gel ice packs in reasonable quantities may use the medical exception even when melted or slushy. Notify the officer and expect inspection.
Cooling accessories for formula, breast milk, toddler drinks, or baby and toddler food also receive separate screening treatment. These can include ice packs, freezer packs, frozen gel packs, and other cooling materials, whether or not breast milk is present. Present partly frozen or slushy packs with the nourishment items.
Check Connections And Safety Rules
Review duty-free liquids on connections
Duty-free status does not exempt a product from every later U.S. checkpoint. The key questions are whether the itinerary requires another screening and which authority controls that checkpoint.
For an inbound international trip with a connecting U.S. flight, TSA’s liquids rule permits duty-free liquids over 3.4 ounces or 100 milliliters in carry-on baggage only when the retailer packed them in a transparent, secure, tamper-evident bag, the bag shows no sign of tampering, and the traveler presents the original receipt for a purchase made within the previous 48 hours. The items still must be screened and cleared. Do not open the sealed bag before the last applicable checkpoint.
Another country or connection may apply a different rule. Check whether the itinerary requires re-screening, then verify the security and airline instructions for every transfer. If the item or bag does not meet the applicable checkpoint conditions, move it to checked baggage only when checked carriage is otherwise allowed. Do not treat a duty-free purchase like a medical or infant-nourishment exception.
For alcohol, TSA’s alcoholic beverages guidance applies ordinary carry-on liquid treatment where relevant, including the 3.4-ounce or 100-milliliter limit and quart-bag requirement for carry-on mini bottles. FAA and airline policies may impose separate alcohol quantity and transport rules.
Keep TSA and FAA questions separate
TSA screening determines whether an item can pass through a checkpoint. FAA PackSafe determines whether an item is a dangerous good and, if so, whether it may travel in carry-on baggage, checked baggage, or not at all.
Check both systems for products containing fuel, pressure, flammable ingredients, corrosive material, batteries, or another hazardous component. Liquid volume alone does not answer the dangerous-goods question. A small aerosol or container may still need a separate safety review because of its contents or pressure.
The same rule applies to checked baggage. Moving an item out of the cabin does not automatically make it safe or permitted for air transport. Use the FAA PackSafe passenger guidance for hazardous-material questions, then review airline and destination requirements separately.
Use this packing sequence
- Identify whether the item is ordinary, medically necessary, infant or child nourishment, a cooling accessory, or a possible dangerous good.
- Put ordinary liquids, aerosols, gels, creams, and pastes in containers of 3.4 ounces or 100 milliliters or less.
- Place ordinary containers in one clear quart-sized zip-top bag per traveler.
- Keep medical items, nourishment, and qualifying cooling accessories separate and accessible.
- Declare exceptions before screening and follow the officer’s instructions.
- For ambiguous products, consult the live TSA item list.
- Check FAA PackSafe for products involving fuel, pressure, flammability, corrosiveness, batteries, or other hazards.
- Review connection, airline, and destination-entry rules for duty-free goods and other restricted products.
For broader baggage planning, use the Baggage collection. For airport planning beyond liquid screening, use the Airports collection.
Is Everything Over 3.4 Ounces Prohibited?
No. The 3.4-ounce or 100-milliliter limit is the default for ordinary liquids, aerosols, gels, creams, and pastes. Medically necessary liquids and eligible formula, breast milk, toddler drinks, and baby or toddler food can use separate screening procedures outside the quart bag.
An exception does not guarantee admission, remove the need for inspection, or allow unlimited quantities. Declare the item, carry a reasonable amount for its purpose, allow time for separate screening, and remember that TSA officers make the final checkpoint decision.
Apply These Rules When Packing
- Classify first: Before measuring an item, decide whether it is ordinary, medically necessary, infant or child nourishment, a cooling accessory, or a possible dangerous good.
- Use 3-1-1 for ordinary items: Each ordinary liquid, aerosol, gel, cream, or paste must be 3.4 ounces or 100 milliliters or less and fit in one clear quart-sized bag per traveler.
- Separate exceptions: Declare medical liquids, formula, breast milk, toddler drinks, baby food, and qualifying cooling accessories for separate screening.
- Check both systems: Use TSA’s item search for checkpoint classification and FAA PackSafe for dangerous-goods restrictions.
- Plan for discretion and connections: Even permitted categories can receive added screening, and duty-free status does not assure passage through a later checkpoint.
FAQ
Does every liquid have to fit in the quart-sized bag?
No. The quart-sized bag applies to ordinary liquids, aerosols, gels, creams, and pastes. Eligible medical liquids and infant or child nourishment can be carried outside the bag through separate screening.
Can liquid medicine exceed 3.4 ounces?
Yes. Medically necessary liquids, medications, and creams may exceed 3.4 ounces or 100 milliliters in reasonable quantities for the trip. Declare them and prepare to present them separately.
Does breast milk have to fit in the 3-1-1 bag?
No. Breast milk, formula, toddler drinks, and baby or toddler food can exceed the ordinary limit and do not need to fit in the quart bag. Tell the TSA officer about them before screening.
Can I bring gel ice packs for medicine or breast milk?
Possibly. Ordinary gel packs generally need to be frozen solid. Medically necessary and child-nourishment cooling accessories can receive separate screening. Present partly melted or slushy packs for inspection.
Are duty-free liquids always permitted on a connecting flight?
No. A later checkpoint may apply different requirements. Check whether the itinerary requires re-screening and review applicable airline, foreign-security, and destination rules.
What if TSA’s item list does not clearly describe my product?
Search TSA’s current What Can I Bring list for the closest category. Treat the result as guidance, not a guarantee. If the product contains fuel, pressure, flammable or corrosive material, batteries, or another possible hazard, check FAA PackSafe too.