Foxglove plants by a stone wall. Foxglove plants (Digitalis purpurea) contain a poisonous chemical, digitalin. Consuming the plant causes vomiting, hallucinations and death from disorganised pumping of the heart. In modern medicine, drugs based on the poison are used to treat heart failure, arrhythmia (irregular heartbeat) and fibrillation (rapid, disorganised heartbeat). The most commonly-used drugs derived from the foxglove are digoxin and digitoxin. The foxglove is a common plant throughout much of Europe. It grows on waste land and in woods. It can produce flower spikes over a metre tall. Photographed in the Ben Mor Coigach Reserve, Ross-shire, Scotland.