Foxglove (Digitalis purpurea) in Pets

Foxglove contains digitalis-type heart glycosides in every part. See which signs suggest heart involvement, why vase water counts, and what to tell your vet.

What It Is

Foxglove is a tall cottage-garden plant with spikes of tube-shaped purple, pink or white flowers. It contains digitoxin and related cardiac glycosides, the original source of the heart drug digitalis. Every part is toxic, including the seeds, and water from a vase of cut foxgloves can carry the toxins too.

Where Pets Come Across It

Gardens, woodland edges and road verges in Europe and North America, and cut-flower arrangements. Dogs may chew leaves of young plants before they flower, when foxglove is easy to mistake for harmless foliage.

Which Animals Are Affected

Dogs, cats, horses, livestock and birds are all susceptible.

Published Toxic Dose

No owner-usable mg/kg threshold is published for pets, because glycoside content varies with the plant part and season. The ASPCA and Pet Poison Helpline list foxglove as toxic, and small amounts of leaf can affect the heart. The calculator does not score a dose for foxglove.

Signs and How Soon They Appear

Vomiting, drooling, diarrhoea and abdominal pain, usually within a few hours, then heart effects: a slow or irregular heartbeat, weakness, collapse and, in severe cases, death.

What to Do Right Now

Call your vet or a poison line and mention 'foxglove' so the heart can be monitored. Take a leaf or flower stalk with you. Do not induce vomiting at home.

Recognising foxglove before it flowers

Foxglove is a biennial. In its first year it forms a flat rosette of soft, hairy, greyish-green leaves with toothed edges, close to the ground; in the second year it sends up a flower spike up to 1.5 m tall with bell-shaped flowers spotted inside. The first-year rosette is easily mistaken for comfrey or borage, and that confusion has poisoned people as well as animals. It self-seeds freely, so new plants appear in borders and along shaded paths each year. If you have dogs that chew greenery, pull young rosettes while wearing gloves, remove spent flower spikes before they shed seed, and keep cut stems out of vases that pets can reach. Grazing animals rarely eat fresh foxglove because it tastes bitter, but dried plants in hay are a recognised risk for horses and cattle.

Foxglove and the heart drug digoxin

Foxglove is the plant behind digitalis medicines, first described for heart failure by the English physician William Withering in 1785. Modern digoxin tablets prescribed to people (and sometimes to dogs by vets) act in the same way as the plant glycosides, so a pet that swallows a family member's digoxin tablets is at risk of a similar heart poisoning. Keep all heart medicines in closed cabinets. If a pet eats a tablet, the dose on the label lets a poison line estimate the risk far more precisely than is possible for a chewed plant, so bring the packet with you.

Frequently Asked Questions

Sources and References

• ASPCA: Foxglove
• Pet Poison Helpline: Foxglove
• Merck Veterinary Manual: Houseplants and Ornamentals Toxic to Animals

Related Poisons