The snake plant, known scientifically as Dracaena trifasciata (formerly Sansevieria trifasciata), is a resilient houseplant often recognized as Mother-in-Law’s Tongue. Its distinctive, upright, sword-like leaves add vertical interest to indoor spaces. It is renowned for its low-maintenance requirements, thriving even with infrequent watering and in conditions ranging from low to bright light.
The Plant’s Nighttime Oxygen Release (CAM Photosynthesis)
The snake plant employs a unique biological mechanism known as Crassulacean Acid Metabolism (CAM photosynthesis), an adaptation for survival in arid environments. Unlike most plants that open their stomata during the day to take in carbon dioxide, the snake plant keeps its stomata tightly closed. This drastically reduces water loss through evapotranspiration.
The gas exchange shifts to the cooler, darker hours of the night. The stomata open to absorb carbon dioxide, which is chemically converted into malic acid and stored within the plant’s cell vacuoles.
Once daylight returns, the stomata close, and the stored malic acid is broken down to release carbon dioxide internally. This sequestered carbon dioxide feeds the photosynthetic process during the day, powered by light energy. This metabolic cycle means the snake plant actively takes in carbon dioxide and releases oxygen during the night, contributing a small but steady amount of oxygen to a closed indoor environment.
Filtering Specific Indoor Air Contaminants
The snake plant plays a role in absorbing certain common pollutants found in homes and offices. Studies, including the NASA Clean Air Study, confirmed that the plant can metabolize specific Volatile Organic Compounds (VOCs) from the air. These VOCs are carbon-containing chemicals that off-gas from household products like paints, furniture, carpets, and cleaning supplies.
The plant is noted for its ability to absorb formaldehyde (released by pressed wood and fabrics), benzene (found in plastics and fibers), and trichloroethylene (present in adhesives and dry cleaning chemicals). It can also take up xylene, a compound used in the printing, rubber, and leather industries.
These filtration effects were measured in sealed laboratory chambers with high pollutant concentrations, which do not reflect a typical home environment. The actual impact of a few snake plants on air quality is quite small compared to proper ventilation. While the plant can filter toxins, its practical contribution is minor. It is best viewed as a supportive measure, rather than a primary air purification device.
Safety Concerns Regarding Toxicity
While the snake plant offers aesthetic and biological benefits, it possesses a mild level of toxicity if ingested, a consideration for households with pets or small children. The plant’s defense mechanism involves naturally occurring chemical compounds called saponins. Saponins can irritate the gastrointestinal system when consumed.
If a cat or dog eats the leaves, saponins can trigger symptoms such as nausea, vomiting, diarrhea, and excessive drooling. The ASPCA lists the species as toxic to canines and felines, necessitating careful placement away from curious pets. In humans, ingestion typically leads to minor irritation of the mouth and throat, along with possible upset stomach.
The toxicity level is considered low, and life-threatening reactions are rare. The bitter taste usually discourages consumption of enough plant material to cause severe harm. Owners should place the snake plant on high shelves or in inaccessible areas to prevent ingestion.