Every part of the plant is poisonous because it contains about 20 poisonous glycosides such as convalatoxin, convalarin, and convalamarin, as well as saponins. They cause poisoning characterized by strong headache, nausea and vomiting, slow pulse and excessive urination. The victims are often domesticated animals because the may lily is a widely distributed cultivated plant.

Convallaria majalis Copyright © Thomas Schöpke, http://www.plant-pictures.com

May lily is 15 to 30 or 40 cm high, has two 10 cm long and 4-10 cm wide leaves and small fragrant white blossoms. It grows in places, having an altitude of up to 1400 m. The fruit is a bright-red strawberry. 

Its glycosides were used in the past as a source of medical products for cardiology but they have already been replaced by more effective medicines.