What plant, often mistaken for wild onion, contains neurotoxic alkaloids?

The plant often mistaken for wild onion that contains neurotoxic alkaloids is death camas. Its underground bulbs resemble edible camas and onion-family plants, especially after the leaves and flower stalks disappear. Unlike true onions, death camas lacks a distinctive onion smell, and its toxic compounds are not destroyed by ordinary cooking.

Death camas refers to several North American species, including Toxicoscordion venenosum. Its principal toxin is the neurotoxic alkaloid zygacine, which can cause nausea, vomiting, numbness, weakness, slowed heartbeat, low blood pressure, breathing problems, seizures, and death. Livestock, particularly sheep, are also vulnerable when grazing early-season pastures.

A common mix-up is with edible camas lilies, wild onions, and garlic. The similar bulbs are the main danger; the plants are easier to distinguish when flowering. The name “death camas” reflects both its visual similarity to edible camas and its severe toxicity.