Propolis and Flying: A Natural Way to Support Your Mucosal Barrier

You come home from holiday feeling great. Three days later you can barely speak.

It's rarely bad luck, though. And the reason (and help) starts somewhere you might not expect. With bees 🐝. Stay with me!

Why do we get ill after flying?

Even setting aside stress, which is often a huge factor, a few physical things stack up when you travel by plane. You're sitting for hours in a shared space, breathing air that's been around the cabin a few times, with a few hundred people who have all come from somewhere different and are all bringing their own regional collection of viruses. You've probably been up since the early hours too.

Each one of these things nudges your immune resilience down a little. And importantly - you may unknowingly have a breach in one of your main areas of defence.

Your mucosal barrier - your first line of defence

Long before your immune system reaches for antibodies, you have a quieter first line of defence: the moist lining that covers everywhere your (inside) body meets the outside world. It runs through your nose, throat and airways, and all the way down through your gut - one continuous, working surface.

In the airways it works like a slow conveyor belt. A film of mucus catches dust, bacteria and viruses, and tiny hair-like cilia beneath it sweep them up and away before they settle. In the gut, a similar mucus layer shields the lining and keeps your resident microbes where they belong. Different tissues, same quiet job - catching what comes in and clearing it before your immune system has to get involved.

Thing is, your mucosal barrier only works well when it stays moist. Which is where flying causes trouble.

Why flying dries out your mucosal barrier?

Cabin air is drier than most deserts, often around 10 to 20% humidity.

After a few hours, that moist lining dries out, the mucus thickens and the whole system slows - just as it meets a few hundred people's worth of unfamiliar viruses. Although the recirculated air is filtered rather well (or so we're told!). It's the dryness that does the damage.

Which brings me, at last, to the bees.

What is propolis, and why was I thinking about bees?

Bees don't just make honey. They also make propolis (from Greek for 'in defence of the city') which they use to protect their hive. They collect resin from tree buds and bark, mix it with beeswax and their own enzymes, and use the result to seal cracks, line the walls and keep the whole colony from being overrun by bacteria and fungi. A hive is warm, damp and crowded, which should be a microbial paradise. The fact that it isn't is largely thanks to propolis.

Can propolis stop me catching something on a plane?

Studies using propolis on planes haven't yet been done. But there are some interesting studies that help us infer how it may help.

• The main one is a randomised, double-blind, placebo-controlled trial in 122 adults with mild upper respiratory infections, using a standardised poplar-type propolis throat spray or an identical placebo for five days. By day three, 83% of the propolis group had improved versus 72% on placebo, with symptoms clearing around two days earlier. Not to be sniffed at!

• In children, a trial of 430 one to five year olds found that a preparation containing propolis with echinacea and vitamin C, taken for 12 weeks, reduced both the number of illness episodes and the number of days with fever.

• A separate trial found propolis with zinc reduced recurrent ear infections in 122 young children, with no safety or tolerability problems reported.

• And in a rather different setting, hospitalised COVID patients given standardised green propolis alongside standard care had a shorter hospital stay than those on standard care alone - a median of six to seven days versus twelve.

So, my honest read: propolis may not stop you catching something, but can shorten and soften it. That's worth having in your bag before six hours of breathing everyone else's air.

Why does this matter more if you have IBD?

If you or your child lives with Crohn's or ulcerative colitis, you'll know that a "simple" cold is rarely simple.

Infections are one of the recognised triggers for a flare. The immune system is already working in a dysregulated way, and asking it to mount a response to a respiratory virus on top of that can be enough to tip things. Add in the disrupted sleep, the different food, the change in routine and the sheer physical demand of travelling, and holidays can be a genuinely tricky time even when everything goes well. Many families I work with feel extra anxious, both for the trip and also for the fortnight after they return too.

So the question of "can I avoid getting ill, or at least get over it faster" is a bigger question in IBD than it is for most people. It isn't just about the cold. It can be about what the cold might set off.

Propolis is being studied for inflammatory bowel disease in its own right, and how it does so is particularly interesting - I'll do a separate blog on that later - if you're interested you can subscribe here so you don't miss it. But for now, we're just looking at simple ways to support your barriers during travel, in the hope of reducing one known flare trigger.

Beyond the basics: why the word "propolis" on a label means almost nothing

Here's the bit most articles skip, but for it's an important aspect.

Propolis is not one substance. Its chemistry depends entirely on which trees the bees visited. Bees in Europe work mostly from poplar buds, and European poplar-type propolis is rich in flavonoids like galangin, chrysin, pinocembrin, apigenin, pinobanksin and quercetin. Bees in south-eastern Brazil work from a plant called Baccharis dracunculifolia, and Brazilian green propolis is defined by a compound called artepillin C, which barely appears in European propolis at all. Red propolis, from Cuba and northern Brazil, is different again.

These are, chemically speaking, three different products sold under one word.

This is why the studies matter so much. The throat spray trial didn't test "propolis" - it tested a poplar-type extract standardised to a known polyphenol content, with a reproducible flavonoid profile, batch after batch. That standardisation is the study. A random jar of raw propolis scraped from a hive somewhere is not the same intervention, and it may not do the same thing.

The key takeaway - if you're choosing a product, the type and the standardisation are really important.

Is propolis safe?

Mostly yes, with one caveat: propolis is a recognised allergen.

It's common enough that it was added to the European baseline patch test series in 2019, and roughly 1% to 7% of people patch tested for dermatitis react to it.

In one study of 1,255 children patch tested over eight years, 5.9% reacted, and the rate climbed year on year as propolis products grew more popular. Reactions can be triggered by swallowing it, not only by skin contact, and it cross-reacts with balsam of Peru.

So: skip it if you're allergic to bee products, start cautiously with children, and try it at home before you rely on it in an airport.

Two practical notes. Many tinctures are alcohol-based, which I'd avoid for children and for anyone with an irritated gut. And propolis stains everything it touches a determined orange-brown. You have been warned!

What else helps at this particular moment?

Here's why it's important to understand what's going on behind the scenes. There are more ways than just propolis to give support to your mucosal layers whilst on a plane.

Drinking water on a flight isn't about hydration in the vague wellness sense - it's about keeping the barrier working while it's under a very specific stress.

And a plain saline nasal spray is one of the most underrated things you can carry, doing physically what the cabin is undoing. There's a small pilot trial with people who used hypertonic saline nasal irrigation and gargling at the onset of a cold. Their illness was shortened by around 1.9 days, they used 36% fewer over-the-counter medicines, and passed it on to 35% fewer members of their household. Saline is typically a great cheap and safe intervention - for adults and children.

The other unglamorous one we all remember from Covid days. Cold viruses travel by hand more than most people realise. Tray tables are not famous for their hygiene - worth a quick wipe if you can. And just in general - washing your hands before eating and keeping them off your face as much as possible is great advice.

So what would I pack?

A standardised poplar-type propolis throat spray, used on the plane and for a few days afterwards - the window when exposure has happened but the virus hasn't got going yet. A saline nasal spray. A small packet of wet wipes. A water bottle - refillable at most airports.

I'd skip a raw unstandardised propolis product, because I'd have no idea what was in it.

And I'd hold all of it in perspective. Propolis is a small, sensible addition to a decent foundation - never a substitute for one. The goal isn't to bulletproof yourself. It's to give your body everything it needs to thrive, so that when it does meet something, it copes really well.

Post for information only - not to be construed as medical advice. I always advise seeking individual personalised guidance before adding any supplements into your schedule, and particularly for children.

References

1. Esposito C, Garzarella EU, Bocchino B, et al. A standardized polyphenol mixture extracted from poplar-type propolis for remission of symptoms of uncomplicated upper respiratory tract infection (URTI): a monocentric, randomized, double-blind, placebo-controlled clinical trial. Phytomedicine. 2021;80:153368.

2. Cohen HA, Varsano I, Kahan E, et al. Effectiveness of an herbal preparation containing echinacea, propolis, and vitamin C in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled, multicenter study. Archives of Pediatrics & Adolescent Medicine. 2004;158(3):217-221.

3. Silveira MAD, De Jong D, Berretta AA, et al. Efficacy of Brazilian green propolis (EPP-AF) as an adjunct treatment for hospitalized COVID-19 patients: a randomized, controlled clinical trial. Biomedicine & Pharmacotherapy. 2021;138:111526.

4. Ramalingam S, Graham C, Dove J, Morrice L, Sheikh A. A pilot, open labelled, randomised controlled trial of hypertonic saline nasal irrigation and gargling for the common cold. Scientific Reports. 2019;9:1015.

5. de Groot A, Rustemeyer T. Contact allergy to propolis: update 2013-2025. Dermatitis. 2025.