The plant widely known as Coleus, or Painted Nettle, belongs to the Plectranthus genus, often classified under the synonyms Solenostemon scutellarioides or Coleus blumei. This species is globally popular for its strikingly colorful foliage, making it a common garden and houseplant staple. Due to its widespread ornamental use, questions about its edibility and safety often arise. Whether one can eat Coleus depends entirely on the specific species, but the common garden varieties are generally considered mildly toxic and are not safe for consumption.
Understanding Different Coleus Species
The confusion regarding Coleus edibility arises because the name applies to hundreds of cultivars and several distinct species with different chemical profiles. Most plants sold in nurseries, recognized for their vibrant, velvety leaves, are ornamental varieties of Solenostemon scutellarioides. These plants are cultivated purely for aesthetic purposes and carry a risk of toxicity if ingested.
Medicinal vs. Ornamental Varieties
A separate species, Coleus forskohlii (or Plectranthus barbatus), is traditionally used in Ayurvedic medicine. The root of this species contains a compound called forskolin, which is extracted and highly concentrated for use in dietary supplements. This medicinal use of concentrated root extract is completely different from consuming the raw leaves and stems of ornamental varieties. The presence of the same genus name has led to the misunderstanding that the leafy garden plants are interchangeable with the medicinal species. Ornamental varieties are not cultivated for the same chemical properties as the medicinal roots, nor are they safe to eat. Consuming the leaves of brightly colored garden plants is strongly advised against.
The Toxicity of Ornamental Coleus
The common ornamental Solenostemon scutellarioides is considered mildly toxic to humans and animals due to the presence of specific chemical compounds. The primary toxic agents are certain essential oils and diterpenoids, such as coleonol, which is closely related to forskolin. These compounds are present in the leaves and stems and are responsible for the plant’s irritant properties.
The nature of the toxicity is twofold, involving both contact and ingestion. Direct contact with the sap or leaves can cause skin irritation, known as contact dermatitis, in sensitive individuals. This reaction typically manifests as a mild, temporary rash or redness. If the ornamental Coleus is consumed, the irritating essential oils can cause gastrointestinal distress. While the overall toxicity level is generally low and rarely life-threatening, ingestion is strongly discouraged.
Ingestion Symptoms and Safety Protocols
If a human or pet ingests part of an ornamental Coleus plant, the symptoms are typically localized to the digestive system. Common signs of ingestion in both humans and pets include vomiting, diarrhea, and general abdominal discomfort. Pets may also exhibit excessive drooling, lethargy, or pawing at the mouth due to irritation. In some cases, more severe symptoms like bloody diarrhea or vomiting, anorexia, and depression have been reported in animals.
Safety Protocols
If suspected ingestion occurs, immediate action is necessary to ensure safety. For humans, wash the mouth and any affected skin thoroughly with water. Contacting a regional Poison Control Center or a healthcare provider is the most prudent step for advice. For pets, a veterinarian or the ASPCA Animal Poison Control Center should be contacted without delay. When seeking professional advice, provide a sample of the plant for positive identification and estimate the amount consumed. Keeping ornamental Coleus plants out of the reach of curious children and pets is the most effective preventive measure.