How to Get Rid of a Smell in a Mattress

1. Work out what the smell is

• Urine or vomit from a child or a pet. It needs an enzyme cleaner (step 3).
• Sweat and body odor. Years of it build up in the top layer. Baking soda and fresh air help (steps 4 and 5).
• Musty or mildew. The mattress is staying damp. See step 6.
• A chemical smell from a new mattress. That’s off-gassing, and it fades. See the last section.

2. Strip, wash, and vacuum

Take off everything, including the mattress protector and pad, and wash it all on the hottest setting the labels allow. Then vacuum the whole mattress, including the sides and seams, with the upholstery tool.

3. Treat urine and other stains

For a fresh accident, blot up as much as you can with towels. Press hard, and don’t rub.

Then use an enzyme cleaner. The Humane Society recommends enzyme cleaners for urine because they break it down instead of masking it. Use enough to reach as far down as the urine did, leave it as long as the label says, and blot.

Don’t pour water on a mattress or steam it. Foam holds water for days, and a damp mattress grows mildew. If you can’t see where an old stain is, shine a UV flashlight over the mattress in a dark room.

For urine on carpet and furniture too, see our cat urine and dog smell guides.

4. Deodorize with baking soda

Once any wet spots are dry, sift a thin layer of baking soda over the whole top. Leave it for several hours, or overnight if you can sleep somewhere else. Vacuum it all up.

5. Dry and air it

Air and sunlight help a mattress lose its smell. On a dry, sunny day, put it by an open window or outside on a clean sheet for a few hours. Indoors, point a fan at it and keep the window open. Flip or rotate it so both sides get air.

6. If it smells musty

A musty mattress is a damp mattress. Common causes are a mattress on the floor or on a solid platform with no airflow, a humid bedroom, or a spill that never dried. Raise it on a slatted base, keep bedroom humidity below 60%, and check the underside for spots. If mold is growing inside, the EPA notes that porous materials like this often can’t be cleaned. See musty smell in your house to find the source of the damp.

7. Protect it

Put a waterproof mattress protector on once the mattress is completely dry. It keeps sweat and accidents out of the foam, and you can wash it with the sheets.

New mattress smell

The smell from a new foam mattress comes from gases released by the foam and glues. The EPA’s general advice for these is to increase ventilation. Unwrap the mattress in a room with the windows open and let it air out for a day or two before you sleep on it. Most of the smell is gone within a couple of weeks.