Peace Lily Benefits: What This Common Houseplant Actually Does (and Doesn't Do)
Peace lilies (Spathiphyllum spp.) are one of the most popular indoor plants in the world — and one of the most misunderstood when it comes to health claims. Understanding what they realistically offer, and where the evidence stops, helps set accurate expectations.
What Is a Peace Lily?
The peace lily is a flowering tropical plant commonly kept indoors for its glossy leaves and distinctive white blooms. It's not a true lily — it belongs to the Araceae family — and importantly, it is not edible. All parts of the plant contain calcium oxalate crystals, which are toxic if ingested by humans or pets.
Its reputation for "wellness benefits" comes primarily from its role as a living object in an indoor environment, not from any nutritional or medicinal use.
The Air Quality Question 🌿
Most peace lily health claims trace back to a 1989 NASA Clean Air Study, which tested a range of houseplants for their ability to remove volatile organic compounds (VOCs) — chemicals like benzene, formaldehyde, and trichloroethylene — from sealed chamber air.
Peace lilies performed well in that controlled setting. The study is real, peer-reviewed, and frequently cited.
What the research actually showed:
- Plants absorbed measurable amounts of several indoor air pollutants in a small, controlled chamber environment
- Microbial activity in the soil contributed to some of this absorption
- Peace lilies were among the more effective plants tested
What the research did not show:
- That houseplants meaningfully improve air quality in typical residential or office conditions
- That the effect is large enough to influence human health outcomes
A 2019 review published in the Journal of Exposure Science & Environmental Epidemiology found that you would need hundreds of plants per square meter of floor space to achieve the air filtration rates that a standard HVAC system or even passive ventilation provides. Most homes and offices simply don't operate under the sealed, low-airflow conditions used in the NASA study.
The honest summary: peace lilies can absorb some airborne compounds, but the real-world air quality impact in a typical lived-in space is likely very small.
Humidity and Indoor Environment
Peace lilies release moisture through their leaves via transpiration, which can contribute slightly to indoor humidity levels. In very dry environments — particularly in winter months when heating systems reduce relative humidity — plants collectively may add a small amount of moisture to the air.
Whether this has any meaningful effect on respiratory comfort, skin hydration, or sleep quality in a specific household depends on the existing humidity levels, room size, number of plants, and individual sensitivity. The contribution of a single plant is modest.
Psychological and Environmental Wellbeing
This is where some of the more credible research exists — though it's worth understanding its scope.
A growing body of research in environmental psychology suggests that exposure to indoor plants and natural elements may be associated with:
- Reduced self-reported stress and anxiety in workplace and hospital settings
- Modest improvements in mood and attention in some controlled studies
- A general preference for environments with natural elements, sometimes called biophilic design
Studies in this area vary considerably in quality. Many are small, short-term, or rely on self-reported outcomes. The mechanisms aren't fully established — it's unclear whether observed effects relate to air changes, visual aesthetics, the act of caring for a plant, or something else entirely.
What's reasonably supported: Being around plants — including peace lilies — may contribute to a sense of calm or environmental satisfaction for some people. This aligns with broader research on nature exposure and psychological wellbeing.
What's not established: That a peace lily specifically, or any particular species, produces measurable health improvements in individuals.
Who Might Experience Different Outcomes
| Factor | Potential Influence |
|---|---|
| Allergy or asthma status | Pollen or mold in soil may be irritants for sensitive individuals |
| Pet ownership | Peace lily is toxic to cats and dogs — relevant safety consideration |
| Stress levels and environment | Those in high-stress or sterile environments may notice more psychological effect from greenery |
| Room size and ventilation | Affects any possible humidity or air quality contribution |
| Number of plants | Single plant vs. multiple plants changes any environmental effect |
The Toxicity Consideration
This distinction matters: peace lilies are not safe to eat or apply topically. Calcium oxalate crystals cause mouth and throat irritation, swelling, and gastrointestinal distress if ingested. They are listed as toxic to cats, dogs, and humans by the ASPCA and poison control organizations.
This separates them entirely from edible plants, herbs, or supplements where nutritional or medicinal properties might be measured and discussed in terms of intake.
What the Research Gap Looks Like
The peace lily sits at the intersection of interior design, environmental psychology, and indoor air quality science — three areas where research is active but still developing. Claims that circulate online often extrapolate well beyond what the original NASA study or subsequent research actually demonstrated.
The benefits that are reasonably supported — potential psychological comfort from living with plants, minor environmental contributions — depend heavily on who is in the space, what that space looks like, and what baseline conditions exist. Someone managing severe allergies, living with pets, or hoping for meaningful air purification may find that the reality of a peace lily's role in a home doesn't match its reputation.
Those factors — your specific environment, health sensitivities, and what you're actually hoping to achieve — are what determine whether a peace lily is a meaningful addition to your space or simply an attractive one.
