What “breathing easier” can realistically mean
Houseplants can make a room feel fresher, add a little humidity, and make time at home more pleasant. What they cannot do, on the evidence we have, is replace ventilation, filtration, or medical care. If you are looking for plants to help with a breathing condition, treat them as decoration with possible mood benefits, and speak to a doctor about managing the condition itself.
What the research says
The idea that houseplants clean air traces mostly to a NASA study from the late 1980s. Researchers placed plants in small sealed chambers and measured the drop of certain chemicals such as formaldehyde and benzene. Some plants reduced those chemicals in the chamber over time.
The catch is that a sealed chamber is very different from a home. In real buildings, outdoor air constantly replaces indoor air. Later reviews of this research have concluded that the effect of houseplants on indoor air in ordinary homes is small compared with ventilation, and that it would take an impractical number of plants to match it. Health organizations such as the American Lung Association have said much the same. That does not mean plants do nothing, but a pot on the shelf is not an air purifier.
Plants commonly recommended
These are the plants that most often appear on air-quality lists. Choose them because they are easy and attractive, and do not expect measurable results.
Spider plant
Hardy and fast-growing in bright indirect light. Generally listed as non-toxic to cats and dogs, though chewing can still upset a stomach.
Snake plant
Handles low light and dry spells. Toxic to cats and dogs if chewed.
Boston fern
Soft fronds that like humidity and constant moisture, which many homes cannot provide. Generally listed as non-toxic to cats and dogs.
Areca palm
A bright-room palm that is generally listed as non-toxic to pets. It needs steady watering and dislikes cold air. Our indoor palm care and yellow leaves guide covers common palm problems.
Bamboo palm
A clumping palm (often Chamaedorea seifrizii) that tolerates moderate light. Generally listed as non-toxic to cats and dogs.
Peace lily
Glossy leaves and white blooms. Toxic to cats and dogs, and irritating to people who chew it, because of calcium oxalate crystals. See sensation plant vs peace lily if you are unsure what you have.
Pothos
Easy trailing plant for moderate to low light (see indoor plants that grow downwards for similar vines). Toxic to cats, dogs, and people if chewed.
Dracaena
Upright, tolerant of average indoor light (see is dracaena an indoor plant). Toxic to cats and dogs.
Pet and child safety summary
| Plant | Commonly listed toxicity |
|---|---|
| Spider plant | Generally non-toxic to cats and dogs |
| Boston fern | Generally non-toxic |
| Areca palm | Generally non-toxic |
| Bamboo palm | Generally non-toxic |
| Snake plant | Toxic to cats and dogs |
| Peace lily | Toxic to cats and dogs |
| Pothos | Toxic to cats, dogs, and people |
| Dracaena | Toxic to cats and dogs |
| English ivy | Toxic to pets and people if eaten |
“Non-toxic” is not a promise that a plant is safe to eat. Large amounts of any plant can upset a stomach. If a pet or child has chewed an unknown or toxic plant, contact a veterinarian or poison control service promptly.
Is there a single most air-purifying plant?
No. Lists differ, the studies were done under artificial conditions, and the results vary by chemical. Anyone naming a “most purifying” houseplant is overstating what the evidence can support. A better question is which plant you will keep alive, because a dead plant helps no one.
If you have asthma or allergies
Plants are not a treatment, and they can add a few problems of their own: wet soil can grow mold, dust collects on leaves, and some plants shed pollen or have strong scents. If you are sensitive, consider these steps:
- Choose a small number of plants rather than filling a room.
- Let the soil surface dry between waterings and avoid standing water in saucers.
- Wipe leaves with a damp cloth.
- Keep plants out of the bedroom if they seem to trigger symptoms.
Talk with your doctor about what is right for your situation. See also the best plants for bedrooms.
Good plants for bathrooms
Bathrooms are humid but often dim. Plants that cope with humidity and moderate light include Boston fern, pothos, and snake plant. Without a window, none of them will thrive for long, so a plant light or a different room may be needed. Humidity also means mold can grow, so ventilate the room.
The “78% airborne mold” claim
You may have seen a claim that a particular plant removes 78% of airborne mold. We have not found reliable, replicated evidence for it, and we recommend not relying on it. Plants can also be a mold source when the soil stays wet. If you have a mold problem, find and fix the moisture source.
Better ways to improve indoor air
- Ventilate with windows, kitchen and bathroom fans.
- Use a vacuum with a good filter and dust regularly.
- Avoid smoking indoors and limit burning candles and incense.
- Consider a portable air purifier with a HEPA filter if particles are a concern.
- Control moisture to limit mold.
For questions about oxygen specifically, read plants that give oxygen 24 hours a day. If you are wondering about one popular plant, see whether a monstera is air purifying.