Frankie Apothecary Soothing Oat Bath Soak pouch with finely milled colloidal oatmeal on a speckled plate and in a ceramic bowl, rolled oats scattered beside it

Colloidal Oatmeal Baths for Dry, Itchy Skin: What They Are and How to Run One

September 30, 2026

Colloidal oatmeal is oat that has been milled so finely it forms a colloid in water. Instead of sinking to the bottom of the bath, the tiny particles spread through the water and stay suspended, turning it soft and milky and leaving a light, silky film on the skin. It is one of the oldest skincare ingredients we know of, and still one of the gentlest.

If you have ever sat on the edge of the bath at 7pm with a wriggly, scratchy little one, or felt your own shins prickle every time the heater goes on, you will know why people keep coming back to it. Here is what colloidal oatmeal actually is, what the research does and does not say, and exactly how to run an oat bath at home.

What is colloidal oatmeal?

Colloidal oatmeal is made by grinding and processing the oat grain into a very fine powder. "Colloidal" describes what happens next: put it in water and the particles disperse and hang there, rather than settling like porridge oats do.

That fine texture matters. It is what lets oat spread evenly through the bath and settle onto the skin as a soft, comfortable layer.

Oats are naturally rich in:

Starches and sugars, which give oat water its silky, slippery feel
Beta-glucans, which hold onto water
Lipids (natural oat oils), which help the skin feel soft rather than tight
Proteins, which help buffer the skin's pH
Avenanthramides, a group of compounds found only in oats, which researchers have studied for their soothing effect on itchy skin

People have been bathing in oats for a very long time. Oatmeal was used on the skin in ancient Egypt and Arabia, and ready-to-use colloidal oatmeal has been sold since the 1940s [1].

The milk test. Stir a teaspoon of colloidal oatmeal into a glass of warm water. It should turn cloudy and milky, and feel silky between your fingers. That is the colloid at work.

Close-up of finely milled colloidal oatmeal on a speckled ceramic plate with a wooden spoon

What does the research say about colloidal oatmeal?

The clearest finding is that colloidal oatmeal helps skin hold onto moisture. The research is promising but small, and it is worth knowing who did it.

Here is the honest picture:

Skin hydration. A 2026 review that pooled the trials on colloidal oatmeal found its clearest, most consistent effect was improved skin hydration [5].
Dry skin. In a study of 50 women with very dry skin on their lower legs, an oat lotion improved dryness, moisture levels and skin barrier measures [2].
Itchy, eczema-prone skin. In two small 14-day studies, people with mild to moderate eczema used a 1% colloidal oatmeal cream and researchers recorded better skin hydration and lower itch scores [3]. An earlier review of oat moisturisers and cleansers, used alongside people's usual care by babies, children and adults, found them well tolerated [4].
Who did the research. Several of these studies were run by scientists working for the company behind a large international oat skincare brand [2], [3]. That does not make them wrong, but it is why we would like to see more independent work.

The bath is only half the routine

We think of an oat bath as comfort and preparation. It softens the skin, calms the itch-scratch moment at bath time and makes bedtime gentler. The step that counts comes next: sealing that moisture in with a balm while skin is still damp.

How to run an oat bath, step by step

Two heaped tablespoons of colloidal oatmeal in a lukewarm bath, a 10-minute soak, pat dry, then balm within three minutes. That is the whole routine. Here it is in detail:

Run the bath lukewarm, not hot. Hot water feels lovely but strips the skin's natural oils. For pēpi, test the water on the inside of your wrist.
Add the oat under the running tap. Two heaped tablespoons of Soothing Oat Bath Soak into a partially filled bath and stir until the water turns milky.
Soak for about 10 minutes. Longer is not better. Staying in too long can leave skin drier than when you started.
Pat, don't rub. Lift out and pat gently with a soft towel, leaving the skin slightly damp.
Seal it in within three minutes. Smooth Kawakawa Balm on dry or itchy skin while the skin is still damp. It is water-free, so it sits on the skin and holds that bath-time moisture in. For skin that just needs a lighter layer, Kawakawa Body Oil works too.
Dress in something soft. Loose cotton pyjamas are kindest on freshly balmed skin.

How often? Two or three evenings a week is a good place to start. Some families do it nightly during a dry spell. Watch how your skin responds and adjust.

Heads up: oat baths can be slippery. Keep a hand on little ones the whole time, and give the tub a quick rinse afterwards.

Toddler in a milky colloidal oatmeal bath with Frankie Apothecary Soothing Oat Bath Soak.

Can I give my baby an oat bath?

Yes. A lukewarm oat bath is one of the gentlest options for pēpi and tamariki with dry, itchy or eczema-prone skin, and it fits easily into a calm bedtime routine. A few things make it work well:

Patch test first. Dab a little oat mixed with water on a small patch of skin and wait a day before a full bath.
Keep it short and lukewarm. Five to 10 minutes is plenty for babies.
Skip it on broken skin. If skin is cracked, weeping or looks infected, leave the bath for now and check in with your GP or Plunket nurse.
Oat allergy. If your child has a known oat allergy, give oat products a miss.
Balm within three minutes. A thin layer of Kawakawa Balm on damp skin, then soft cotton pyjamas.

Night-time itch

If you are reading this because bedtime has become a battle, you are not alone. One of the questions parents ask us most is how to stop a toddler itching at night. An oat bath an hour or so before bed, balm straight after, cotton pyjamas and a cool bedroom make a good starting routine.

Oat bath or Epsom salt bath?

Reach for oats when skin feels dry, tight or itchy; reach for Epsom salts when you want a relaxing soak. Plenty of families alternate.

	Oat bath	Epsom salt bath
What it is	Finely milled oat that forms a milky colloid in water	Magnesium sulfate, a mineral salt
Best for	Dry, itchy, eczema-prone skin	Unwinding, tired muscles, a calm bedtime
How much	2 heaped tablespoons	1 to 2 cups
How long	About 10 minutes	10 to 15 minutes
For babies	Yes, lukewarm and short	Start with half a cup and patch test first
On broken skin	Skip it	Skip it, salt will sting
Afterwards	Kawakawa Balm on damp skin	Kawakawa Balm on damp skin

More on salts in our guide to Epsom Salt Baths for Eczema-Prone Skin: What You Need to Know.

Our Soothing Oat Bath Soak

Our Soothing Oat Bath Soak is very finely milled organic oat kernel flour. No fragrance, no fillers.

It was made to sit alongside our Kawakawa Balm, which has over 800 five-star reviews and is trusted by parents all over Aotearoa. If you want the full routine in one box, the Skin Repair Duo pairs the Oat Soak with Kawakawa Balm: soak, pat, seal.

Shop Soothing Oat Bath Soak

Shop the Skin Repair Duo

Frankie Apothecary Soothing Oat Bath Soak pouch and 60ml Kawakawa Balm jar on a wooden board with fresh kawakawa leaves and white flowers

Frequently asked questions

What is colloidal oatmeal and what does it do for skin?

Colloidal oatmeal is oat milled so finely that it forms a colloid in water, turning a bath milky and silky. It leaves a light film on the skin that helps it hold onto moisture, and it soothes dry, itchy skin. Research on colloidal oatmeal shows its clearest effect is improved skin hydration.

Is colloidal oatmeal good for eczema-prone skin?

Many families with eczema-prone skin find oat baths soothing, and studies of colloidal oatmeal products report better skin hydration and comfort. It works best as part of a routine: a short lukewarm soak, then a balm on damp skin straight afterwards.

Do oatmeal baths actually help?

They help skin feel softer and more comfortable, and colloidal oatmeal is well studied for skin hydration. Follow with a balm on damp skin to hold that moisture in.

Can I give my baby an oat bath?

Yes. Use lukewarm water, keep it to five to 10 minutes, and apply a balm straight after. Always do a patch test first: mix a little oat in water, apply it to the skin for 10 minutes, rinse off and wait 24 hours to check it suits your child's skin. Skip it on broken or weeping skin, and avoid oat products if your child has an oat allergy.

How much colloidal oatmeal do I put in a bath?

Two heaped tablespoons of our Soothing Oat Bath Soak in a partially filled lukewarm bath. Stir under the running tap until the water turns milky, then soak for about 10 minutes.

Oat bath or Epsom salt bath, which is better for itchy skin?

For dry, itchy skin, an oat bath is the gentler choice and the one with more skin research behind it. Epsom salts are better known for a relaxing soak. Many families alternate between the two, always finishing with a rich balm like Frankie Apothecary's Kawakawa Balm within three minutes to help hold moisture in the skin.

Where can I buy colloidal oatmeal in NZ?

Our Soothing Oat Bath Soak is available at frankieapothecary.co.nz, on its own or with Kawakawa Balm in the Skin Repair Duo.

This post is for general information only and is not a substitute for medical advice. Check with your GP, Plunket nurse or specialist about your own or your child's skin.