Is Lily of the Valley Poisonous?

A 2018 study in the Journal of Clinical Laboratory Analysis says lily of the valley grows in cooler climates of North America, Europe and parts of Asia, that the entire plant is toxic, containing cardiac glycosides that cause digitalis-like toxicity, and that its principal toxic cardiac glycoside is convallatoxin. A 2021 study says that, contrary to its attractive appearance, lily of the valley contains many toxins, such as saponins and around 30 cardiac glycosides.

Mix-ups happen. A 2025 botany study says confusing the leaves of Colchicum or Convallaria, the lily of the valley genus, with the leaves of wild garlic has repeatedly led to serious human and animal poisonings. The 2018 study says convallatoxin is known to interfere with serum digoxin measurement using the LOCI digoxin assay and other digoxin assays.

A 2016 case report in CMAJ says hundreds of cardiac glycosides have been isolated from plants across 12 botanical families, including foxglove, yellow oleander and lily of the valley. It lists signs and symptoms of cardiac glycoside toxicity including fatigue, generalized weakness, nausea, vomiting, abdominal pain, diarrhea, irregular heart rhythms, palpitations, chest pain, confusion, delirium, seizures and color vision disturbance.