I have a prescription ointment I'd like to bring in my carry on when flying next week. While it is equivalent to 2.11 ounces it is labelled in grams.

All the TSA FAQ's note ounces and ml, not grams, so I worry that I could get flak.

Is there a chance the TSA is going to confiscate this or argue or otherwise delay me? Does anyone have experience with this?

  • 1
    Do you mean this FAQ?
    – Relaxed
    Jul 3, 2014 at 14:41
  • 4
    those are liquid ounces, not weight ounces Jul 3, 2014 at 17:23
  • @KateGregory oh, the pain!
    – phoog
    Aug 25, 2016 at 20:35

5 Answers 5


Since it's a prescription ointment, it's not subject to the 100 ml / 3.4 fluid ounces rules anyway. Have the prescription label on it and clearly readable, and make sure the name matches the name on your boarding pass and in your passport, and you're fine. (This is more than you technically need because the rules just say "medications" but why give a security officer something to argue with you about?)

(I read about a security blogger who brought two separate one-litre bottles labelled Saline Solution and with official-looking labels on them through security. According to the story when questioned why he needed two, he replied "I have two eyes" and that was good enough for them.)


In my frequent flying experience TSA never bothered to actually check the container size as long as the container looked "small enough" and otherwise didn't deserve attention. They only did that when a container was visibly large.

This is however not a case in some other countries. In Japan Narita, for example, there they will go through every single one of them, and will throw away anything over 100ml. Lost there a nice shaving cream (109 ml) which flew with me through US and Europe on like seven flights in a row.

  • From firsthand experience (well, my wife's experience) at Narita: If you ask, and have not used your free baggage allotment already, they will bag it up and hand-carry it directly to the airline counter (with your ticket and maybe your passport, too) so it can be checked as a normal piece and sent down the conveyor to the plane.
    – Kent
    Aug 26, 2016 at 11:46

I don't know if the TSA also has weight or mass limits but the 3.4-fluid-ounce rule is a volume limit (more-or-less equivalent to 100 ml). In any case, it would seem that the container needs to be smaller than that, by volume. A mass in grams or even in ounces does not directly indicate that.

  • Well the rule also applies to gels, etc.
    – katie
    Jul 3, 2014 at 15:00
  • 3
    @WhyWouldYouUseMyFullName Yes but still by volume, AFAIK.
    – Relaxed
    Jul 3, 2014 at 15:15
  • 2
    I have never had any problem bringing lotions in 100 ml bottles with me. They never looked at the unit. The TSA agents are pretty good at estimating if a container is bigger than permitted. If it can fit in a 100 ml container, you are good. They don't need the measurement on the container.
    – Ida
    Jul 3, 2014 at 17:30

Based on my extensive experience I would not expect you to have any trouble - as long as the number of on the label is below 100 grams.

Many years ago I found a specific brand of deodorant spray that labels all of their products as being "150ml" or "150ml/100g", with the exception of one particular product which, despite being in the exact same size container, is labeled only as "100g".

I regularly (and I mean at least weekly) travel with a can of this "100g" spray in my carry-on bags, and have traveled to over 30 countries doing do. Probably one out of ever 4-5 times the airport security staff look at the can as they presume it is over the allowed size (and in some sense of the word, they are correct) - but to date I have never not been allowed continue with it. I have had a small number of security people who have looked at the can in great detail (including all the fine print on the back) looking for a size other than the clearly-shown "100g" on the front of the can, but they always fail.

I have been told by security staff in some countries that their criteria is that any labels must show below "100ml" AND "100g". ie, "150ml/100g" is not acceptable, but the exact same size can showing only "100g" is.

Obviously your experience may vary - but based on hundreds of trips through security in dozens of countries, I'd suggest you'll be fine!


The TSA and other airport security entities are way too dumb to understand that grams and milliliters are different. Example: I tried to leave London a few weeks ago with a 125 gram jar of Marmite. Now, Marmite is an heavy edible paste with a specific gravity of at least 1.5, so 125 grams of it certainly displaces less than 100ml. There was no point in arguing this to the security doof, so I just let him take it.

  • This does not really answer the question. If you have a different question, you can ask it by clicking Ask Question. You can also add a bounty to draw more attention to this question once you have enough reputation. - From Review Aug 25, 2016 at 18:24
  • 4
    @AndrewLazarus It's obnoxiously written but it does answer the question: it says that there might be problems and gives a specific example. OK, it's not an ointment but I don't see how that matters. Aug 25, 2016 at 19:23
  • Next time take the label off before you go through security. Then come back and tell us what happened!
    – phoog
    Aug 25, 2016 at 20:42

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .