The common foxglove, Digitalis purpurea, is a striking and popular ornamental plant known for its tall spikes of tubular, bell-shaped flowers in shades of purple, pink, and white. Despite its widespread use in gardens, every part of the plant is highly toxic to humans and animals. While the foxglove is undoubtedly a poisonous plant, the answer to whether it is “poisonous to touch” is more nuanced. Casual contact with the foliage or flowers typically poses little systemic risk, but ingestion is extremely dangerous and can be life-threatening.
Dermal Contact: Addressing the “Poisonous to Touch” Question
The primary danger from foxglove is not through simple contact, as the toxic cardiac glycosides are poorly absorbed through intact skin. However, touching the plant is not entirely without consequence for some individuals. Contact with the sap or the fine hairs on the leaves can cause localized skin irritation, such as redness or mild itching.
This localized reaction is an irritation response and does not represent systemic poisoning from the cardiac toxins. The more significant dermal risk comes from accidentally transferring the plant’s compounds from the hands to sensitive areas like the eyes or mouth, or into an open cut.
The Real Risk: Toxicity Through Ingestion
The true danger of the foxglove lies in its potent chemical defense system, active in all parts of the plant, including the leaves, stems, flowers, seeds, and roots. The toxic agents are cardiac glycosides, notably digitoxin and digoxin. These compounds are so powerful they are used in controlled doses as prescription heart medication, but they are present in unregulated concentrations within the plant material.
Upon ingestion, these cardiac glycosides exert their effect by targeting the sodium-potassium pump (Na+/K+-ATPase) on the membranes of heart muscle cells. By inhibiting this pump, the compounds cause an accumulation of sodium ions inside the cell. The subsequent rise in intracellular sodium then impairs the function of the sodium-calcium exchanger.
This chain of events leads to an increase in the concentration of calcium ions within the heart muscle cells. The elevated calcium levels result in two dangerous effects: an amplified, forceful contraction of the heart muscle and a disruption of the heart’s normal electrical conduction system. This direct interference with cardiac function can quickly lead to life-threatening heart rhythm disturbances.
Recognizing Symptoms and Seeking Emergency Help
Symptoms of foxglove poisoning can appear rapidly following ingestion, often involving the gastrointestinal, cardiac, and neurological systems. Early signs of toxicity typically include digestive distress, such as severe nausea, vomiting, abdominal pain, and diarrhea.
As the toxins begin to affect the heart, more serious symptoms develop, including a dangerously irregular heartbeat (arrhythmia), a significantly slowed pulse (bradycardia), or a very rapid pulse. Neurological effects often accompany the cardiac issues, manifesting as confusion, dizziness, headache, or visual disturbances, such as seeing halos around lights.
Any suspected ingestion of foxglove requires immediate emergency medical intervention due to the potentially fatal impact on the heart. If you suspect that a person or pet has consumed any part of the plant, you should call emergency services or a poison control center immediately. Early treatment provides the best chance of a positive outcome.
Safe Handling and Prevention
Gardeners should always wear gloves when handling or pruning the plant to prevent skin irritation and to avoid transferring sap to the face. After any gardening activity involving foxglove, it is essential to wash your hands and tools thoroughly with soap and water.
Prevention involves careful placement of the plant in the garden, ensuring it is situated where children and pets cannot easily access it. It is also wise to avoid planting foxglove near edible plants, such as herbs, that might be mistaken for its leaves. Finally, do not use the plant material in home remedies, teas, or compost, as the toxins remain potent even when dried.