Foxglove (Digitalis purpurea)

Tier 4 — risky / avoid · Cardiac glycoside · Fatal

Source plant for the cardiac drug digoxin. Contains cardiac glycosides that cause fatal arrhythmias at doses only slightly above therapeutic levels. Narrow margin of safety. Multiple annual deaths from people mistaking it for a safe herbal tea. Even the pharmaceutical version (digoxin) requires careful blood level monitoring. Never use the raw plant.

Dose: AVOID completely; contains cardiac glycosides that cause fatal arrhythmias; prescription digoxin requires blood monitoring