Is Foxglove Poisonous?

University of Wisconsin-Madison Extension says compounds in common foxglove have been used medicinally, both historically and in more recent medical applications, but that all parts of the plant are toxic if ingested and contact with the leaves can irritate sensitive skin. A 2016 case report in CMAJ says foxglove is one of many plants containing cardiac glycosides, which have potent effects on heart tissue, and that the medically important glycosides digitoxin and digoxin are extracted from Digitalis purpurea and Digitalis lanata, respectively.

It gets mistaken for edible plants. A 2019 case report says foxglove leaves are frequently confused with borage, which is traditionally used as a food ingredient, and that because of cardiac glycosides, mostly digitoxin, foxglove leaves are poisonous to humans and may be fatal if eaten. A 2016 BMJ Case Reports article describes a 63-year-old woman who drank a remedy of boiled comfrey leaves and developed vomiting, palpitations, near-fainting episodes and heart block, with raised serum digoxin levels confirming likely mistaken ingestion of foxglove, and who recovered after digoxin-binding antibodies. It notes an earlier case in China in which neighbors sharing comfrey tea on a farm mistakenly drank foxglove, leading to nine hospitalizations, three requiring cardiac pacing.

The BMJ Case Reports authors say digitalis toxicity, from foxglove plants or from digoxin or digitoxin medication, can affect the cardiovascular, gastrointestinal and visual systems, with irregular heart rhythms, palpitations, fainting, shortness of breath, nausea, vomiting, abdominal pain and yellow-green visual disturbances.