How to Get Smells Out of a Mattress

Start by working out what the smell is

The right fix depends on the cause. A few common ones:

Sweat and body oils. Usually a stale or sour smell that builds slowly, often worse in warm weather.
Urine or pet accidents. A sharp smell that can return when the mattress gets damp or humid.
Mildew or damp. A musty, “basement” smell. This often points to moisture trapped in or under the mattress.
Smoke or cooking odors. These cling to fabric and foam and tend to need airing plus repeated deodorizing.
A new mattress. Some new foam mattresses have a mild smell at first that usually fades with airing. If it does not, check with the manufacturer.

Wash the bedding first. Sheets, pillows and the mattress protector are often the real source, and a smell that seems to come from the mattress may be partly coming from them. See how to clean pillowcases for the pillow end of the bed.

Safety first

Please read this before using any cleaning product on a bed.

Never mix cleaning products. Do not combine bleach with vinegar, ammonia or any acid. Do not combine bleach with ammonia. Urine contains ammonia compounds, so avoid bleach on urine-soiled mattresses. These combinations can release harmful gases.
Do not mix vinegar and hydrogen peroxide in one bottle. Together they can form a corrosive acid. If you want to use both, use them separately, rinse or blot between them, and let the area dry. Many cleaning guides skip over this.
Ventilate the room. Open a window and use a fan while you work and while the mattress dries.
Keep children and pets away until the mattress is fully dry and any powder is vacuumed up. Store all cleaners and powders out of reach.
Be careful with essential oils. Some are harmful to pets, especially cats, and can irritate small children. Skipping them is the safer choice.
Patch test any liquid on a hidden area first, and check the care label or the maker’s instructions. Some warranties are affected by certain cleaning methods.

The basic deodorizing method

This works for most general odors on most mattress types.

Strip the bed. Remove sheets, protector and any removable cover. Wash them according to their labels.
Vacuum the whole surface. Use the upholstery attachment, going over the top, sides and seams. If the mattress can be turned or flipped, vacuum the other side too.
Cover with baking soda. Sprinkle a fairly even layer over the surface. A sifter or sieve helps spread it thinly.
Wait. Leave it for several hours, or overnight for stronger odors.
Vacuum thoroughly. Take your time, because leftover powder can irritate skin and airways and is not something to leave where pets or children sleep.
Air the mattress. Let it sit uncovered, ideally with a window open or a fan running, before remaking the bed.

How long to leave baking soda on a mattress

Sources vary. Guidance ranges from around 30 minutes for a light refresh to several hours or overnight for stronger odors. A few hours is a reasonable middle ground. Longer is fine as long as the powder is dry and no one will disturb it. If the mattress is damp, dry it first, because baking soda on a wet surface can turn into a paste that is harder to remove.

Does baking soda really remove smells?

It can help absorb moisture and some odors, which is why it is so widely recommended. It is not a cure for a smell that comes from deep inside the mattress, and it does not kill mites or bacteria. Think of it as a good first step, not a guarantee.

Fixes for specific smells

Sweat and body odor

Body oils soak deeper than the surface. After the baking soda step, lightly dampen a clean cloth with cool water and a small amount of mild detergent, blot affected areas (do not rub), then blot with a cloth dampened in plain water and press with a dry towel. Use as little liquid as possible, especially on foam. Some guides suggest mixing baking soda with cornstarch to draw out oils, which is gentle and low risk.

Urine and pet smells

Blot up as much as you can first, without rubbing. An enzyme-based cleaner made for pet or urine odors is often the best fit, because it is designed to break down the odor source. Follow the product label. A light mist of equal parts white vinegar and water is another common approach; blot it up, let it dry, then use baking soda. Do not use bleach or ammonia-based cleaners. For a full walkthrough, see our guide on cleaning a mattress after bed wetting.

Musty or mildew smells

A musty smell means moisture, so drying matters more than anything you spray. Get the mattress into a well-ventilated room, stand it on its side if you can, and run a fan. A light mist of diluted vinegar is often suggested, but let it dry thoroughly. Check the underside and the bed base for mold. If you can see mold spread across the mattress, or if anyone in the home has asthma or a mold allergy, consider whether replacing the mattress is the safer choice. Mold on a mattress is hard to remove fully from inside.

Smoke and new-mattress smells

Airing is the main tool. Repeated baking soda treatments, a stripped bed and open windows over a few days help. Strong fragranced sprays tend to mask rather than fix the problem.

Getting stains out of a mattress when dry

Dry stains are harder, but you can often reduce them:

Vacuum first to remove loose dirt.
Lightly dampen the stain with cool water or a small amount of mild detergent solution. Do not soak.
Blot with a clean white cloth, working from the edge toward the center.
For urine or organic stains, an enzyme cleaner (following its label) is a common choice.
Blot with a damp cloth to remove residue, then press with dry towels.
Dry completely with a fan.

A hydrogen peroxide and baking soda mix with a drop of dish soap is widely used on pale mattresses. It can lighten colors and damage some covers, so test first, use a freshly mixed solution, and do not store it in a sealed bottle. Hydrogen peroxide of about 3 percent is the usual drugstore strength.

Drying and airing out

Moisture is the main thing to avoid. After any liquid treatment:

Blot with dry towels to take out as much as you can.
Use a fan, open windows or a dehumidifier.
A hair dryer on a low or cool setting can help on small spots if you keep it moving.
Do not put sheets on until the mattress is completely dry to the touch, including the inside layers if possible.

What to use and what to avoid

Generally reasonable: vacuum, baking soda, mild detergent, plain water, enzyme cleaners made for fabric, white vinegar diluted with water (lightly misted), fans and airing.

Better to avoid: bleach, ammonia, heavy soaking, steam on foam unless the maker allows it, and strongly scented sprays that cover the smell without removing it.

Some mattress types need extra care. See our guides for latex mattresses, bamboo-cover mattresses and Japanese futons.

Keeping a mattress from smelling again

Use a washable mattress protector and wash it regularly.
Wash sheets weekly or when they feel damp or smell.
Let the bed air for a short time each morning before making it.
Make sure the base allows air flow underneath.
Keep bedroom humidity moderate where you can.
Vacuum the mattress now and then. Many sources suggest deep cleaning about twice a year, though there is no single rule.

If dust is part of the problem, see how to reduce dust mites in a mattress.

When a smell will not go away

If you have repeated the process and the smell remains, the source may be deep in the mattress, the base, or the room. Consider:

Checking the base and floor underneath for damp or mold.
Contacting the manufacturer, especially if the mattress is new or under warranty.
Asking a professional cleaner whether they can treat the mattress.
Replacing the mattress if it is old, sagging, or has persistent mold or heavy urine contamination.