A lukewarm bath with colloidal oatmeal or baking soda is one of the most effective ways to ease sunburn pain and itching at home. The key is keeping the water cool, choosing the right additives, and knowing what to skip. Here’s what actually works and how to do it right.
Water Temperature Matters Most
Before adding anything to your bath, get the temperature right. Lukewarm or cool water is essential. Hot water strips your skin’s protective barrier, increasing water loss from already damaged tissue. Research published in the Journal of Clinical Medicine found that hot water exposure significantly damages skin barrier function compared to cold water, even after just 10 minutes of submersion. For sunburned skin, which is already inflamed and losing moisture faster than normal, hot water makes everything worse.
Aim for water that feels neutral or slightly cool against your inner wrist. Keep the soak to about 10 to 20 minutes. Longer soaks, especially beyond 30 minutes, can dry out your skin further by depleting its natural oils.
Colloidal Oatmeal
Colloidal oatmeal is finely ground oatmeal that dissolves into bathwater and coats your skin with a thin, soothing film. It’s the most well-studied bath additive for inflamed skin. The active compounds, called avenanthramides, block the release of inflammatory chemicals and histamine in your skin. That translates to less redness, less itching, and less of that tight, burning sensation.
You can buy colloidal oatmeal packets (Aveeno is the most common brand) at any drugstore. One packet per bath is standard. If you want a DIY version, blend plain, unflavored oats in a food processor until they’re a fine powder, then add about a cup to your bathwater and stir until the water looks milky. The oat particles should dissolve rather than sink to the bottom.
Baking Soda
Baking soda is another reliable option, especially if itching is your main complaint. It dissolves completely in water and helps neutralize the acidic environment on irritated skin. The National Eczema Association recommends adding a quarter cup of baking soda to a lukewarm bath for itchy, inflamed skin. You can use up to two cups for a full tub, though starting with a quarter cup is a good idea to see how your skin responds.
Stir it around until it’s fully dissolved before getting in. Baking soda works well on its own, and you can combine it with colloidal oatmeal if you want the anti-itch benefits of both.
Cool Milk
Adding a few cups of cold whole milk to your bath is a classic sunburn remedy with some real science behind it. Milk contains lactic acid, which gently helps clear dead skin from the surface of the burn, along with proteins and antioxidants that reduce inflammation. The cold temperature provides immediate cooling relief on contact. Whole milk works best because of its higher fat content, which helps coat and protect the skin. Pour two to four cups directly into your cool bathwater.
Apple Cider Vinegar
Apple cider vinegar is a polarizing option. Some sources, including WebMD, note that a vinegar bath can ease sunburn pain, inflammation, and itching. Others caution that its acidity can further irritate damaged skin, particularly if your burn is severe or blistering. If you want to try it, add one to two cups to a full tub of cool water so it’s well diluted. Start with a small area first. If it stings or your skin feels more irritated after a few minutes, get out and rinse off with plain water.
What to Leave Out of the Bath
Sunburned skin is essentially an open wound, and many common bath products contain ingredients that will make it worse. Skip anything with fragrance, dyes, or heavy surfactants. That means no bubble bath, no scented bath bombs, no body wash with sodium lauryl sulfate. Fragrances in particular can increase your skin’s sun sensitivity and trigger further irritation.
Rubbing alcohol and hydrogen peroxide are also common mistakes. Both strip moisture and damage healing skin cells. Essential oils like lavender or tea tree are sometimes recommended for sunburn, but adding them directly to bathwater is risky. They don’t dissolve in water and can sit on your skin in concentrated drops, causing irritation or even contact burns on already damaged tissue. If you want to use essential oils, apply them after the bath, diluted in a carrier oil, to a small test area first.
What to Do After the Bath
How you dry off and what you do in the next 60 seconds matters almost as much as what was in the bath. Don’t rub yourself with a towel. Gently pat your skin until it’s damp but not dripping, then immediately apply a fragrance-free, dye-free moisturizer while your skin is still slightly wet. This traps moisture against your skin and helps rebuild the barrier that sunburn has compromised. Aloe vera gel, plain petroleum jelly, or a product like Aquaphor all work well for this step.
Avoid “after sun” lotions that contain alcohol, menthol, or lidocaine in the first day or two. While they feel cooling initially, alcohol-based products accelerate moisture loss, and numbing agents like lidocaine can cause allergic reactions on inflamed skin.
Signs a Bath Isn’t Enough
A soothing bath works well for mild to moderate sunburn, the kind that’s red, tender, and uncomfortable but doesn’t have large blisters. If your sunburn comes with large fluid-filled blisters, blisters on your face or hands, a fever over 103°F, vomiting, confusion, or signs of infection like pus or red streaks spreading from the burn, you need medical attention rather than a home remedy. These symptoms can indicate sun poisoning or a second-degree burn that requires professional treatment.