17 Jul 2026
The flea/washing up liquid cheat sheet:
- Washing up liquid can cause fleas to sink and drown in water.
- It may help remove fleas from a pet during bathing.
- It won't tackle a full flea infestation on its own.
- It doesn't reliably eliminate flea eggs and larvae around your home.
- Vets recommend dedicated flea treatments for long-term control.
- If you're washing pet bedding, a good detergent is still your best friend.
Yes fleas are tiny, but they can turn a perfectly peaceful home into an itchy nightmare.
Interestingly, one of the internet's favourite hacks to get rid of them is Washing Up Liquid.
So, does it genuinely work? Or is it just another cleaning myth?
Let's find out.
Why does washing up liquid seem to kill fleas?
Fleas are tough! They can even walk on water thanks to its surface tension (the same reason certain tiny insects can skate across a pond without sinking).
Add a drop of washing up liquid to the water though, and it’s a different story.
The surfactants in washing up liquid reduce the surface tension of water so fleas can no longer stay on the surface and may sink and drown instead. It’s why homemade flea traps often suggest:
- A shallow bowl of water
- A few drops of washing up liquid
- A light source to attract fleas
Can you use washing up liquid on pets?
A bath with washing up liquid may remove some adult fleas from a dog or cat, but most vets don't recommend relying on it as a flea treatment.
❌ | It only affects the fleas currently on the pet. |
❌ | It doesn’t tackle things ongoing. |
❌ | It doesn't get rid of eggs or larvae around your home. |
❌ | Frequent washing will dry out your pet's skin and coat. |
If your pet has fleas, it's best to speak with your vet about treatments rather than relying on washing up liquid.
What about smol Washing Up Liquid?
Like other washing up liquids, smol Washing Up Liquid contains surfactants that help break down grease and food residues.
It will reduce water's surface tension just like other washing up liquids, but it wasn’t designed or tested as a flea treatment.
Our zesty Pink Grapefruit was made for sparkling dishes rather than tackling parasites.
What actually gets rid of fleas?
The fleas you can see (the adults) are often only a small part of the problem because a flea life cycle involves eggs, larvae, pupae and then the adult fleas.
Most of these stages don’t happen on your pet - they take place in:
- Carpets
- Soft furnishings
- Pet bedding
- Cracks and crevices
So successful flea control means treating both pets AND your home.
Washing pet bedding.
Wash bedding regularly while treating the infestation. That doesn’t just mean your dog or cat beds, but blankets, cushion covers, throws… basically any washable fabrics your pet sleeps on.
For best results:
- Follow the care label instructions.
- Wash at the highest temperature suitable for the fabric.
- Dry items thoroughly before reuse.
How to stop fleas coming back.
To help lower the chances of fleas returning:
✅ | Vacuum carpets and upholstery regularly. |
✅ | Wash pet bedding frequently. |
✅ | Keep up with vet-recommended flea prevention. |
✅ | Empty vacuum contents promptly. |
✅ | Check pets regularly, especially during warmer months. |
Washing up liquid and flea FAQs.
Catherine Green, Cleaning Expert
Catherine has been on a mission to revolutionise the way we tackle chores since the dawn of smol and is an advocate for making more sustainable living accessible to all, with a strong focus in cleaning that’s heavy on dirt, lighter on the planet and gentle on the skin. Catherine has tested hundreds of hacks to make tackling chores easier, safer, and better for the planet and our homes.
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