Making a baking soda and hydrogen peroxide paste takes about 30 seconds and requires just two ingredients you probably already have. The standard ratio is 2 parts baking soda to 1 part hydrogen peroxide, mixed until you get a thick, spreadable consistency. This simple paste works for both teeth whitening and household cleaning, though the application method differs depending on what you’re using it for.
The Basic Paste Recipe
Start with 2 tablespoons of baking soda in a small bowl. Add 1 tablespoon of 3% hydrogen peroxide (the standard concentration sold at drugstores). Stir with a spoon until the mixture forms a smooth, thick paste similar to the texture of toothpaste. If it’s too runny, add a pinch more baking soda. If it’s too dry and crumbly, add a few more drops of peroxide.
The paste will fizz slightly when you first mix it. That’s normal. Hydrogen peroxide reacts with baking soda to release oxygen, which is part of what gives the paste its cleaning and whitening power. Mix a fresh batch each time you use it rather than storing it, since the reaction loses effectiveness over time.
Using the Paste on Teeth
For teeth whitening, apply a small amount of the paste to your toothbrush and brush gently for about two minutes, then rinse thoroughly. Some people load the paste into a mouth guard and leave it on for up to 10 minutes. Either way, the hydrogen peroxide works by breaking down pigment molecules that cause yellowing, while the baking soda provides mild physical scrubbing.
Baking soda is actually one of the gentlest abrasives you can use on teeth. It scores a 7 on the Relative Dentin Abrasivity scale, which measures how much a substance wears down tooth structure. For comparison, most commercial toothpastes score between 50 and 150. So the baking soda itself isn’t the concern. The hydrogen peroxide is what you need to be careful with.
Stick with 3% hydrogen peroxide, the kind in the brown bottle at the pharmacy. Concentrations above 6% increase the risk of enamel damage and gum irritation. Signs that the paste is bothering your gums include soreness, redness, inflammation, or white patches on the gum tissue. White spots are a sign of a chemical burn. If you notice any of these, stop using the paste immediately.
Lab research has shown that hydrogen peroxide combined with baking soda does reduce yellow discoloration on teeth over repeated applications. The effect is real but gradual, working primarily on surface stains from coffee, tea, or wine rather than deeper discoloration. The American Dental Association notes that limited research exists on DIY whitening methods compared to commercial products, and one study found that a strawberry-and-baking-soda mixture (a popular alternative) produced no measurable whitening at all.
Using the Paste for Household Cleaning
The same 2:1 ratio of baking soda to hydrogen peroxide works as an effective grout cleaner, and adding a small squirt of dish soap (about 2 teaspoons per cup of baking soda) makes it cling better to vertical surfaces. For a standard cleaning session, mix 1 cup of baking soda with ½ cup of hydrogen peroxide and the dish soap, then stir into a thick paste.
Spread the paste along grout lines with a spoon or your fingers, working in small sections at a time. Let it sit for 5 to 10 minutes, then scrub each grout line with a stiff brush. You’ll see the grout lighten as you scrub. After scrubbing, sweep up the dried residue and follow with a mop or damp rag using hot water and a bit of dish soap to remove any remaining film.
This same paste works on a variety of surfaces: tile, sinks, bathtub rings, baking sheets, and stained countertops. For baking sheets, spread the paste on, let it sit for a few hours or overnight, then scrub and rinse. The combination of mild abrasion from the baking soda and the oxidizing action of the peroxide lifts stains that neither ingredient handles as well on its own.
Tips for Getting the Right Consistency
The most common mistake is adding too much liquid at once, which turns the paste into a thin slurry that slides off whatever you’re trying to clean. Add the hydrogen peroxide gradually, a few drops at a time after the first tablespoon, until you reach a consistency that holds its shape on a spoon. For grout cleaning, you want it slightly thicker than toothpaste so it stays in place during the waiting period. For teeth, a slightly thinner consistency works better since it needs to spread evenly.
Use the paste within a few minutes of mixing. As the hydrogen peroxide breaks down, the mixture loses its oxidizing power and eventually becomes just wet baking soda. If you need to clean a large floor area, mix smaller batches as you go rather than one large bowl that sits while you work your way across the room.