The quick answer
Colloidal oatmeal is whole oat grain milled into a powder so fine that it spreads through bath water instead of sinking. The FDA lists it as an over-the-counter skin protectant that temporarily relieves minor itching and irritation from eczema, rashes, poison ivy, oak or sumac, and insect bites. Dermatologists suggest it as a lukewarm bath soak for itchy, dry skin, but it soothes symptoms rather than curing the underlying condition.
Babies and young children with eczema can become sensitized to oat proteins in skin products. If your child has eczema, ask their doctor before using oat creams or baths regularly, and stop if the skin gets redder or itchier.
What is colloidal oatmeal?
"Colloidal" describes particles small enough to stay suspended in a liquid. Colloidal oatmeal starts as the whole oat kernel, ground and processed until it feels like soft flour. Sprinkled into running bath water, it spreads through the tub instead of collecting on the bottom, so it reaches every patch of itchy skin.
People have put oats on irritated skin for centuries. A ready-made colloidal oatmeal for the bath went on sale in 1945, and the preparation is now standardized by the United States Pharmacopeia (Kurtz and Wallo, Journal of Drugs in Dermatology, 2007).
Is colloidal oatmeal FDA approved?
It is one of the active ingredients allowed in the FDA's rules for nonprescription skin protectants (21 CFR Part 347). A product using it must contain at least 0.007 percent, or at least 0.003 percent when paired with mineral oil. Bath products must give directions that reach at least 0.007 percent in a full tub and 0.25 percent for a foot bath or compress.
The rule also sets the label wording. Products may say they temporarily protect and help relieve minor skin irritation and itching from rashes, eczema, poison ivy, oak or sumac, and insect bites. Every label must tell you to stop and ask a doctor if the problem gets worse or lasts more than seven days. Because 0.007 percent is only a minimum, lotions and creams vary, so check the Drug Facts box for the percentage.
How does colloidal oatmeal soothe skin?
Oats bring several helpful compounds at once. Their starches and beta-glucan form a protective, water-holding film, and oat saponins cleanse gently (Kurtz and Wallo, 2007).
- Avenanthramides: phenolic compounds in oats, at roughly 300 parts per million. In skin cells and in mice they calmed inflammation and reduced scratching (Sur et al., Archives of Dermatological Research, 2008). That's lab and animal evidence, not proof in people.
- Oat lipids: oat oil is mostly linoleic acid (36 to 46 percent) and oleic acid (28 to 40 percent). In cell studies it switched on genes tied to the skin barrier and ceramide production (Lin et al., International Journal of Molecular Sciences, 2017).
- pH buffering: colloidal oatmeal extracts helped hold skin-friendly pH in lab tests (Ilnytska et al., Journal of Drugs in Dermatology, 2016).
Colloidal oatmeal for eczema and itchy skin
The American Academy of Dermatology (AAD) lists a colloidal oatmeal bath among the home steps that give quick, short-term relief from itchy childhood eczema, and suggests the same soak for chickenpox itch. The real goal, it notes, is getting eczema itself under control.
Human studies are encouraging but small. In two single-group trials of about 30 people each with mild to moderate eczema, a 1 percent colloidal oatmeal cream used for two weeks was linked with less itch, better eczema scores and better-hydrated skin (Lisante et al., Journal of Drugs in Dermatology, 2017). Neither trial had a comparison group. In 50 women with very dry lower legs, an oatmeal lotion improved dryness (Ilnytska et al., 2016).
| Colloidal oatmeal | Regular oatmeal (rolled or steel-cut) | Oat oil | |
|---|---|---|---|
| What it is | Whole oat grain milled to a very fine powder that disperses in water | Flattened or chopped kernels made for cooking | Fat taken from the oat kernel |
| FDA status on skin | Recognized OTC skin protectant | Not an OTC drug ingredient | Not an OTC drug ingredient; a cosmetic oil |
| Key skin compounds | Starches, beta-glucan, avenanthramides, saponins, lipids | Same grain, but too coarse to spread through water | Linoleic and oleic acids |
| Works in a bath? | Yes, it stays suspended | No. The AAD says breakfast oats in the tub won't relieve itch | Not on its own; better inside creams |
| Best use | Itch-relief baths, compresses, oatmeal lotions | Eating | Moisturizers aimed at the skin barrier |
How to take an oatmeal bath
- Fill the tub with lukewarm water, not hot.
- Sprinkle the amount on the package slowly under the running faucet, then stir up anything that settles.
- Soak 10 to 15 minutes for a child. Adult package directions allow 15 to 30 minutes. Longer soaks can dry some skin.
- Step out carefully, since oat baths are slippery.
- Pat dry so skin stays a little damp, and apply moisturizer within about three minutes.
Don't let young children eat the powder. For poison ivy, oak or sumac, the AAD's first step is washing the plant oil off with warm, soapy water right away. Go to the emergency room for trouble breathing or swallowing, a rash around the eyes, mouth or genitals, a swollen face, or a rash over most of the body.
Can you make it at home? Some people grind plain, unflavored oats in a blender until they become a soft, flour-like powder. If you try it, stir a spoonful into warm water, and if gritty bits sink, keep grinding. A homemade batch isn't tested to the FDA and USP standard, so for reliable itch relief, especially for a child, a labeled product is the safer choice.
Allergy, celiac and other cautions
Oat allergy. Skin reactions to oats aren't as rare as many people assume in young children with eczema. Among 302 children with eczema sent for allergy testing, about 15 percent reacted to oat on a patch test. In kids who had used oat creams, 32 percent reacted, compared with none who hadn't. The authors advised against oat-protein skin products for infants with eczema (Boussault et al., Allergy, 2007).
Celiac disease. Oats don't contain wheat gluten, and a review behind Health Canada's position found that most people with celiac disease can eat oats free of contamination from wheat, barley and rye (La Vieille et al., 2016). Because oats can pick up traces of those grains, choose a product labeled gluten-free if you want to avoid any contact.
When to see a doctor. Skin that looks infected (red, painful or draining) needs a clinician. Our psoriasis cream guide covers another itchy skin condition.
Find it at William's
We don't currently list colloidal oatmeal online; call the store to check what's on the shelf.
If you're curious about other oat products, see our guide to oatstraw. For plant oils used on dry skin, our herbal oils guide explains the differences.
Frequently Asked Questions
What is the difference between colloidal oatmeal and regular oatmeal?
Colloidal oatmeal is milled so fine that it stays suspended in water and coats the skin. Rolled or steel-cut oats are too coarse, and the AAD notes that breakfast oats in the bath won't relieve itch.
Does colloidal oatmeal help eczema?
It can ease itch and dryness for a while. The AAD includes oatmeal baths in its home itch-relief tips for children with eczema, and small studies of a 1 percent oat cream showed less itch over two weeks.
How long should you soak in an oatmeal bath?
The AAD suggests 10 to 15 minutes for children. FDA label directions for bath products say 15 to 30 minutes as needed. Use lukewarm water, pat dry, and moisturize right away.
Is colloidal oatmeal safe for babies?
Infants with eczema can become sensitized to oat proteins. In one study, positive oat patch tests were far more common in children who had used oat creams. Ask your child's doctor first, and stop if the skin gets worse.
Can I use colloidal oatmeal for poison ivy or bug bites?
Yes. FDA labeling allows these products to claim temporary relief of itching from poison ivy, oak or sumac and from insect bites. The AAD advises seeing a dermatologist if the rash covers several areas, blisters badly, looks infected, or is your first one.
Is colloidal oatmeal gluten-free?
Oats don't contain wheat gluten, but they can pick up traces from wheat, barley and rye. If you have celiac disease, look for a product labeled gluten-free.