Clematis, a genus of flowering plants known for their climbing habit and showy blooms, are common in many gardens. These ornamental vines belong to the buttercup family, Ranunculaceae, which contains toxic species. All species of Clematis are toxic if ingested. The toxicity stems from chemical compounds present throughout the plant, including the leaves, stems, and flowers.
The Definitive Answer: Toxicity Status
Clematis toxicity is low-level; ingestion rarely leads to life-threatening complications. The plant’s extremely bitter taste causes immediate discomfort, discouraging consumption before a dangerous dose is reached. Clematis is listed as toxic to domesticated animals, including dogs, cats, and horses.
Curious toddlers and young pets are at the highest risk for accidental poisoning. Although ingestion is usually self-limiting due to the rapid onset of oral irritation, any exposure should be taken seriously. The primary effects are localized irritation to the skin and mucous membranes.
The Toxic Compound and Mechanism
Clematis toxicity stems from an irritant glycoside called ranunculin, a precursor molecule found in buttercup family tissues. When the plant material is chewed or damaged, enzymes break down ranunculin.
This process converts the non-toxic ranunculin into protoanemonin, a highly irritating substance. Protoanemonin is an oily compound that acts as a vesicant, causing blistering upon contact. The immediate burning sensation serves as the plant’s natural defense mechanism.
Protoanemonin is most concentrated in the plant’s sap and leaves, leading to immediate, localized symptoms. The compound is chemically unstable and polymerizes into the non-toxic substance anemonin when dried. This explains why dried Clematis material loses its poisonous nature.
Recognizing Signs of Ingestion
Exposure to Clematis can manifest as dermal contact or ingestion. Dermal contact, often occurring during pruning, can cause localized skin irritation. This irritation may involve redness, a burning sensation, and sometimes mild contact dermatitis or blistering.
Symptoms of ingestion begin immediately due to protoanemonin’s caustic effect on oral tissues. The first signs are a severe burning sensation in the mouth, throat, and tongue. This intense irritation often leads to excessive drooling or salivation.
Gastrointestinal distress quickly follows, including abdominal pain, nausea, and vomiting. Diarrhea is a common reaction. Although rare, ingesting large quantities has been associated with systemic effects, such as dizziness or confusion.
Immediate Steps After Exposure
Immediate action focuses on removing the irritant and seeking professional guidance. For dermal exposure, the affected skin area should be washed thoroughly with soap and water immediately. This removes any remaining sap or protoanemonin residue and minimizes the severity of contact dermatitis.
If ingestion is suspected, immediately rinse the mouth with water to remove plant fragments. Offering small amounts of water or milk may help dilute the chemical irritant in the throat and stomach. Do not attempt to induce vomiting unless specifically instructed by a medical professional or poison control center.
In cases of suspected human ingestion, contact the National Poison Control Center immediately at 1-800-222-1222. For pets, contact your local veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435. Always have the plant name and an estimate of the amount consumed ready when calling for assistance.