Indoor Plants for Health and Wellness: What the Science Says, Plus 12 Easy Picks

Most lists of indoor plants for health promise cleaner air and calmer minds. This guide checks those promises against the research, from the famous 1989 NASA study to newer work on stress and wellbeing. You will also get care basics, pet-safety facts and the folklore behind 12 easy houseplants.

[PHOTO: A bright windowsill with three healthy houseplants of different leaf shapes, photographed in natural light.]

Indoor plants for health: the short answer

Houseplants are good company, and some research links them with small benefits to mood and stress. They are not air purifiers. A few pots on a shelf will not measurably clean the air in a normal home.

Do indoor plants clean the air? The NASA study and what came after

What NASA actually tested in 1989

The air-purifying plant idea traces back to a 1989 NASA report by B. C. Wolverton and colleagues. NASA wanted ways to keep air clean inside sealed space stations. The team put single potted plants in sealed plexiglass chambers smaller than one cubic meter.

They injected one chemical at a time, such as benzene, trichloroethylene or formaldehyde. Then they measured how much was left after about 24 hours. Levels did fall. The report also found that roots and soil microorganisms did much of the work, not just the leaves.

You may have seen the claim that NASA found plants remove “up to 85%” of indoor pollutants. That figure does not appear in the NASA report’s text. The report describes “significant” reductions in its test chambers, without a headline percentage.

Why the results do not apply to your living room

A home is not a sealed box. Air leaks in and out constantly through doors, windows, vents and gaps. That steady exchange dilutes indoor pollutants far faster than any plant can absorb them.

In 2019, Drexel University researchers Bryan Cummings and Michael Waring reviewed about a dozen studies spanning 30 years. They converted the lab results into a “clean air delivery rate,” the standard measure for air purifiers. To match the cleaning effect of normal ventilation, you would need 100 to 1,000 plants per square meter of floor.

Newer research: a small effect on nitrogen dioxide

A 2022 study from the University of Birmingham and the Royal Horticultural Society tested peace lily, corn plant and ZZ plant. Each plant removed roughly half the nitrogen dioxide in a test chamber within an hour. Nitrogen dioxide is a pollutant that comes mostly from traffic.

The researchers then modelled real offices. In a small, poorly ventilated 15 cubic meter office, five plants could cut nitrogen dioxide by about 20%. In a larger 100 cubic meter office, the effect fell to about 3.5%. The mechanism is still unknown, and real-home testing was planned as follow-up work.

The takeaway is simple. Enjoy your plants, but do not rely on them for air quality. If you worry about air at home, ventilation and dealing with the source matter far more.

Indoor plants for wellness: what research says about mood and stress

The wellbeing evidence is more encouraging, though still thin. In 2022, Han and colleagues published a systematic review with meta-analyses in the International Journal of Environmental Research and Public Health. It covered 42 studies that measured physical responses to indoor plants, such as blood pressure and brain waves.

The authors rated study quality as moderate. Most participants were college students, few studies were randomized, and the pooled results relied on two or three studies each. They called for more high-quality research before drawing firm conclusions.

A 2022 study from the University of Reading and the Royal Horticultural Society asked people to rate images of houseplants. Lush, leafy plants with dense, rounded canopies scored highest for making a space feel uplifting and relaxing. Unhealthy, neglected plants had a negative effect, which the researchers said could be worse than no plants at all.

So the honest picture is modest. Plants probably make a room feel nicer, and there are early signs of small physical benefits. They are a pleasant addition to a calm home, not a therapy. If you are struggling with stress, anxiety or low mood, talk to a doctor or mental health professional.

12 easy indoor plants: care, pet safety and folklore

These plants were chosen because they are widely available and forgiving. Pet-safety status follows the ASPCA’s toxic and non-toxic plant lists. Folklore and Feng Shui notes describe tradition, not proven effects.

1. Spider plant (Chlorophytum comosum)

Family: Asparagaceae. Care: bright, indirect light; water when the top of the soil feels dry. It produces small plantlets on arching stems that root easily in water or soil. Pets: listed by the ASPCA as non-toxic to cats and dogs, which makes it one of the best choices for pet owners. More in our spider plant care guide.

2. Golden pothos (Epipremnum aureum)

Family: Araceae. Care: tolerates low to bright indirect light; let the soil dry partly between waterings. Stem cuttings root readily in a glass of water. Pets: toxic to cats and dogs. It contains insoluble calcium oxalates, which cause mouth burning, drooling, vomiting and trouble swallowing. Read our golden pothos guide for more.

3. Peace lily (Spathiphyllum species)

Family: Araceae. Care: low to medium indirect light; it droops visibly when thirsty and recovers quickly after watering. Pets: toxic to cats and dogs, with the same calcium oxalate effects as pothos. Despite its name, it is not a true lily. Symbolism: its white flower is often linked with peace and sympathy, which is why it is a common gift. See our peace lily article.

4. Corn plant and other dracaenas (Dracaena fragrans and relatives)

Family: Asparagaceae. Care: medium indirect light; water sparingly. Brown leaf tips are common and are often linked to fluoride or salts in tap water. Pets: dracaenas are listed as toxic to cats and dogs. The corn plant was one of the three species in the 2022 nitrogen dioxide study. Our dracaena guide compares popular varieties.

5. Snake plant (Dracaena trifasciata)

Family: Asparagaceae. Botanists moved it from Sansevieria into Dracaena, so you may see either name. Care: one of the most drought-tolerant houseplants; overwatering is the main way to kill it. Pets: listed as toxic to cats and dogs. Folklore: its nickname “mother-in-law’s tongue” comes from its sharp, pointed leaves.

6. Lucky bamboo (Dracaena sanderiana)

Family: Asparagaceae. It is not a true bamboo. Care: grows in water or soil in indirect light; change the water regularly and use filtered water if leaves yellow. Pets: as a dracaena, it is listed as toxic to cats and dogs. Feng Shui tradition: the number of stalks carries meaning, for example three for happiness. These are cultural beliefs, not proven effects.

7. ZZ plant (Zamioculcas zamiifolia)

Family: Araceae. Care: tolerates low light and long dry spells thanks to its thick, water-storing roots. It was also tested in the 2022 nitrogen dioxide study. Pets: like other aroids, it contains calcium oxalates, so keep it out of reach of pets and children.

8. Aloe vera (Aloe vera)

Family: Asphodelaceae. Care: a succulent that needs bright light, gritty fast-draining soil and very little water. Pets: toxic to cats and dogs, according to the ASPCA. It contains saponins and anthraquinones, which can cause vomiting, lethargy and diarrhea. Tradition: aloe has a long history of folk use on the skin. Keep it as an ornamental plant, and ask a doctor or pharmacist before using any aloe product on burns or wounds.

9. Weeping fig (Ficus benjamina)

Family: Moraceae. Care: bright, indirect light and a stable spot. It famously drops leaves when moved or chilled. Its lush, leafy canopy is exactly the type the 2022 Reading study rated highest for wellbeing. Pets: toxic to cats and dogs; the ASPCA lists the enzyme ficin and the compound psoralen. The milky sap can also irritate human skin.

10. Bamboo palm (Chamaedorea seifrizii)

Family: Arecaceae. Care: medium indirect light and evenly moist, but never soggy, soil. Watch for spider mites in dry heated rooms. Pets: listed as non-toxic to cats and dogs. The Reading study found palms carried especially positive associations, often linked to holidays and happy memories.

11. Boston fern (Nephrolepis exaltata)

Family: Nephrolepidaceae. Care: bright indirect light, steady moisture and higher humidity, which makes it well suited to a bright bathroom. Dry air turns its fronds crisp and brown. Pets: listed as non-toxic to cats and dogs.

12. Air plants (Tillandsia species)

Family: Bromeliaceae. Care: no soil needed. They take in water through tiny scales on their leaves, so they need regular soaking or misting, then a full dry-off. Bright indirect light and good airflow prevent rot. Symbolism: their soil-free life is often read as a symbol of resilience and independence.

How to match a plant to your room

Light decides more about a plant’s health than anything else, including watering. A plant in the wrong light struggles no matter how carefully you tend it. Start with the light you have, then add your other needs.

“Bright indirect light” means a spot near a window where the sun does not fall directly on the leaves. A room a few steps back from a sunny window often fits. “Low light” means a spot where you can still read comfortably during the day, not a dark corner. No houseplant survives long without some daylight.

Humidity is the next factor. Ferns and palms like moist air, so a bright bathroom or kitchen suits them. Succulents such as aloe prefer dry air and dislike steamy rooms. Grouping humidity-loving plants together creates a slightly moister pocket of air around them.

Temperature matters too. Most common houseplants come from tropical forests and dislike cold drafts. Keep them away from doors that open in winter, and away from radiators and heating vents. Sudden changes are often what cause a weeping fig to drop its leaves.

Quick comparison: care and pet safety at a glance

Pet status follows ASPCA plant listings. Toxicity can vary by species, so check the ASPCA database for the exact plant you own.

Keeping houseplants safe for pets, children and allergies

Many of the most popular houseplants are the ones most likely to cause trouble. Pothos, peace lily, ZZ plant and other aroids contain needle-shaped calcium oxalate crystals. When chewed, they cause immediate burning in the mouth, drooling and vomiting. That pain usually stops pets from eating much, but it still needs a vet’s advice.

• Know what you own. Keep plant tags, or photograph each plant with its name. Toxicity depends on the exact species.
• Place toxic plants out of reach. High shelves and hanging planters work for dogs, but cats can climb. In a cat home, choose non-toxic plants.
• Watch for true lilies in bouquets. Lilies of the Lilium and Hemerocallis types are especially dangerous to cats. Ask your vet if a cat has had any contact with them.
• Teach children not to taste plants, and keep cut stems and fallen leaves picked up.
• Mind sap and allergies. Ficus sap can irritate skin, and some people react to plant pollen or to mold on overwatered soil.
• Act fast if something is eaten. Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 (a fee may apply). For a child, call Poison Help at 1-800-222-1222 in the US.

Plant folklore and symbolism around the home

Houseplants carry centuries of meaning, and that cultural layer is part of their appeal. The beliefs below are traditions, not claims about health or luck.

If you enjoy the mindful side of plant care, our garden and houseplant articles cover individual plants in more depth.

Common mistakes with indoor plants

1. Overwatering. It is the most common way houseplants die. Soggy soil rots roots and attracts fungus gnats. Check the soil with a finger first.
2. Buying plants to clean the air. The research does not support this in homes. Choose plants because you like them, and ventilate for air quality.
3. Trusting “pet-friendly” labels without checking. Store tags can be vague. Look up the botanical name on the ASPCA list.
4. Keeping a struggling plant on display. The Reading study found unhealthy plants made spaces feel worse. Revive it, repot it or compost it.
5. Placing tropical plants by cold windows or heaters. Drafts and dry heat cause leaf drop and brown tips.
6. Ignoring drainage. Pots without holes trap water. Use a nursery pot inside a decorative one so you can empty extra water.

Your one step this week

Walk through your home and write down the name of every plant you own. Check each one on the ASPCA toxic and non-toxic plant list. Move anything toxic out of reach of pets and small children, and save the poison control number in your phone.

Sources

1. Wolverton BC, Douglas WL, Bounds K. A Study of Interior Landscape Plants for Indoor Air Pollution Abatement: An Interim Report. NASA, 1989. NASA technical report (archive.org)
2. Cummings BE, Waring MS. Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies. Journal of Exposure Science and Environmental Epidemiology, 2019. Summary: Drexel University news release
3. Gubb C, et al. Potted plants can remove the pollutant nitrogen dioxide indoors. Air Quality, Atmosphere and Health, 2022. Summary: University of Birmingham news release
4. Han KT, Ruan LW, Liao LS. Effects of Indoor Plants on Human Functions: A Systematic Review with Meta-Analyses. International Journal of Environmental Research and Public Health, 2022; 19: 7454. Full text (PDF)
5. Berger J, Blanusa T, et al. University of Reading and Royal Horticultural Society, Building and Environment, 2022. Summary: Attractive houseplants give biggest wellbeing boost
6. Royal Horticultural Society. Houseplants for wellbeing. rhs.org.uk
7. ASPCA Animal Poison Control. Toxic and Non-Toxic Plant List: entries for peace lily, golden pothos, spider plant, aloe and weeping fig. aspca.org plant list