Yes. TSA names mouthwash as a 3-1-1 liquid, so carry-on bottles must be 3.4 oz (100 ml) or less in your quart-size bag. Larger bottles go in checked luggage.
TSA lists mouthwash among the items covered by the liquids rule: containers of 3.4 oz (100 ml) or less, all in one quart-size bag per passenger.
TSA has no specific checked-bag restriction for mouthwash. Alcohol-based toiletries fall under the FAA medicinal and toiletry exception, whose limits are 500 ml (17 fl oz) per container and 2 L (68 fl oz) per person, so keeping bottles at 500 ml or less is the safe choice.
Checked against official TSA, FAA and government pages on . These are US rules unless we say otherwise; the TSA officer at the checkpoint makes the final call.
The rules in numbers
- Carry-on: 3.4 oz (100 ml) per bottle, in your quart-size bag
- Checked: FAA toiletry caps of 0.5 kg (18 oz) / 500 ml (17 fl oz) per container and 2 kg (70 oz) / 2 L (68 fl oz) per person apply to restricted (e.g. flammable, alcohol-based) toiletries
Packing tips
- Alcohol-free mouthwash or mouthwash tablets avoid any question about flammability.
- Travel-size bottles fit easily in the quart bag; the one-liter bottles most people have at home do not.
Outside the US
- UKLiquids, including toiletries like mouthwash, are capped at 100 ml per container at most UK airports; some allow up to 2 litres. Source
- EUEach liquid container must be 100 ml or less in one transparent bag of up to 1 litre. Source
Flying somewhere else? See the rules for the UK, EU, Canada, Australia, New Zealand, Singapore and Japan.
Questions people ask
Can I bring mouthwash in my carry-on?
Yes, in bottles of 3.4 oz (100 ml) or less inside your quart-size liquids bag.
Can I pack a big bottle of mouthwash in checked luggage?
TSA doesn't restrict it, but because many mouthwashes contain alcohol, keeping each bottle at 500 ml (17 fl oz) or less keeps you within FAA toiletry limits.