According to http://apps.tsa.dhs.gov it says the following:

You may carry liquids, gels and aerosols in your carry-on bags only if they adhere to the 3-1-1 rule: containers must be 3.4 ounces or less; stored in a 1 quart/liter zip-top bag; 1 zip-top bag per person, placed in the screening bin. Larger amounts of non-medicinal liquids, gels, and aerosols must be placed in checked baggage.

Medically required liquids, such as baby formula and food, breast milk and medications are allowed in excess of 3.4 ounces in reasonable quantities for the flight. It is not necessary to place medically required liquids in a zip-top bag. However, you must tell the Transportation Security Officer that you have medically necessary liquids at the beginning of the screening checkpoint process. Medically required liquids will be subjected to additional screening that could include being asked to open the container. We recommend, but do not require, that medication be labeled to facilitate the security process. Many airports have designated lanes for families and individuals with items requiring additional assistance with screening.

The problem is, I've been able to do this once (domestic), however the second time I had it taken away (international).

The time that I had it taken away was when I actually told the dude I had it in my bag, they removed it, kept it, and told me it was not allowed.

Is this up to the discretion of the TSA officer, or is it due to the fact I was in the international terminal versus the domestic terminal? I don't really see the difference.

  • Related: travel.stackexchange.com/questions/7916/…
    – JoErNanO
    Commented Dec 23, 2015 at 14:52
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    Note that it says "in reasonable quantities for the flight" - how much contact fluid do you really need for the duration of a flight?
    – CMaster
    Commented Dec 23, 2015 at 15:42
  • @CMaster It's more of I need it for the flight, as well as my stay at my destination without having to purchase a potential unknown brand which could cause eye irritation. Commented Dec 23, 2015 at 15:43
  • 4
    @JasonHeine quantities of medical liquids for use after you arrive at your destination should be carried in checked luggage if they are over the limit. You should bring a small bottle for the flight and a large bottle for use at your destination, which you ought to be required to check. The fact that one TSA officer allowed you to keep the solution on the flight is probably either a testament to your negotiating skills or a result of the TSA officer being more lenient than she or he is supposed to be. International vs domestic may have played a role, but I doubt it.
    – phoog
    Commented Dec 23, 2015 at 16:04
  • 2
    @JasonHeine Ah, then they just apparently made two different decisions... not unusual for TSA in my experience...
    – Joe
    Commented Dec 23, 2015 at 16:38

3 Answers 3


You quote the TSA:

Medically required liquids, such as baby formula and food, breast milk and medications are allowed in excess of 3.4 ounces in reasonable quantities for the flight.

The key is "reasonable quantities for the flight." For most people, 3.4 ounces of contact lens solution is far more than would be needed for a single flight. If you need more contact lens solution than that for use at your destination, you are supposed to put it in your checked baggage. For longer trips, therefore, you would need two bottles: a small travel bottle for use on the plane and a larger bottle for use after you arrive at your destination.

I don't know why the TSA would have allowed you to take a larger bottle on the domestic flight. I can imagine that any of several reasons might apply. For example:

  • The TSA officer may have been unfamiliar with contact lenses, and therefore unfamiliar with the amount of solution one typically needs to use.
  • The TSA officer may have decided that you didn't represent a threat, and therefore may have exercised discretion (which may or may not have been in keeping with the rules) to allow you to retain the solution.
  • Re-reading your question, I note that you don't say whether you actually discussed the contact lens solution with the officer when you were allowed to keep it. If you did not, they may simply not have noticed it. I've once or twice accidentally carried bottles of liquid through that the TSA screeners missed.
  • If you did discuss the solution with the TSA, as I noted in my comment, it may just be that the TSA officer was not in the mood to argue, or that you are a particularly skilled negotiator. That's kind of frightening, but it's possible.

I do not know whether TSA rules allow laxer screening of domestic flights, but I doubt it.

  • Thank you for this. My question was more out of curiosity than anything, but after all the comments and now a couple of answers, I know that I need to just check it, and get a small bottle for the flight. Thanks again. Commented Dec 23, 2015 at 16:40
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    Bruce Schneier routinely goes through TSA with 24oz Commented Dec 23, 2015 at 19:35
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    @Wayne - "What's allowed?" I asked. "Saline solution, or bottles labeled saline solution?" "Bottles labeled saline solution. They won't check what's in it, trust me." - scary stuff!
    – JBentley
    Commented Dec 23, 2015 at 19:50
  • 1
    @JBentley my personal experience is that TSA is a joke. I made it through security with a Gerber (multi-tool with knives and files) accidentally. I know someone who did the same with a Gerber machete. Ironically, when he was trying to carry baby formula through for his daughter (with her) he got hassled. As a veteran, he was totally thrilled by the experience Commented Dec 23, 2015 at 19:54
  • The problem is getting smaller bottles of contact lens solutions than 120ml: These are not normally sold by vendors. Commented Dec 23, 2015 at 20:22

I don't believe that security should have allowed you to carry the contact lens solution on board on either flight.

In December 1994, Ramzi Yousef smuggled nitroglycerin on board Philippine Airlines flight 434 inside a bottle of contact lens solution, with other bomb parts concealed in his shoes, and assembled a bomb in the lavatory. When the bomb went off, one person died, another 10 were injured, and the plane almost didn't make it back as the bomb damaged some control cables needed to fly the airplane.

(This is the same Ramzi Yousef who bombed the World Trade Center in 1993.)

As a result of this and some similar plots which failed, carry-on liquid containers are restricted in size.

To ensure that you get through security, you should bring a small bottle for use during your flight, and a larger bottle in your checked baggage.

  • Thank you for the information, it's actually good to know. Rather be safe than sorry. Commented Dec 23, 2015 at 16:40
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    What I've never understood is how the rules prevent someone merely splitting their bomb making liquid into multiple small containers? The rule limiting the size of the bag makes sense - the rule for individual bottles inside the bag seems pointless and arbitrary.
    – JBentley
    Commented Dec 23, 2015 at 19:45
  • 2
    @MichaelHampton but empty water bottles are in fact permitted: apps.tsa.dhs.gov/mytsa/…
    – phoog
    Commented Dec 23, 2015 at 19:56
  • 2
    @phoog Welcome to security theater. Commented Dec 23, 2015 at 19:56
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    @Michael You can get access to large containers after security though. Just buy a drink from any number of shops / restaurants before you board the plane. The plastic bag that you carry the small bottles in through security is itself a container. Once you're allowing a combined volume of liquid inside a given container (the bag), then arbitrarily splitting it within the bag achieves nothing (as far as I can see).
    – JBentley
    Commented Dec 23, 2015 at 20:01

The TSA is unclear on this. Quoting the TSA:

3-1-1 Liquids Rule Exemption

You may bring medically necessary liquids, medications and creams in excess of 3.4 ounces or 100 milliliters in your carry-on bag. Remove them from your carry-on bag to be screened separately from the rest of your belongings. You are not required to place your liquid medication in a plastic zip-top bag.

However the TSA elsewhere states:

Medically required liquids, such as baby formula and food, breast milk and medications are allowed in excess of 3.4 ounces in reasonable quantities for the flight.

and elsewhere:

TSA allows larger amounts of medically necessary liquids, gels, and aerosols in reasonable quantities for your trip, but you must declare them to security officers at the checkpoint for inspection.

(this last one is the the quoted above by phoog, and is the exact rule quoted when you search their website for 'contact lens solution')

My understanding is that the first quote is the official rule, and it is the rule most prominently posted on the TSA's website, however I would not rely on it.

Note that I have also had a similar experience with contact lens solution where one officer actually explicitly told me it was allowed, and another explicitly told me it was not.

What was interesting is that in my case, with the rules as written at the time, it all revolved around the liquid bag itself: There was an explicit rule that said you cannot have contact lens solution in quantities over 100ml in your liquid bag and there is a different rule that says you are allowed medically necessary liquids in unlimited quantity. The combination of the two is that if you have large quantities of medically necessary liquids, you are not allowed to have them in your liquid bag, but you can carry them on

...and I actually had a TSA officer make me remove my contact lens solution from the liquid bag so that it met those rules. Apparently my contact lens solution becomes less safe when it's in the liquid bag.

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