Toxic Parts:
phenolic compounds, n-propyl disulfide
Flower Color:
  • flower color
  • flower color
  • flower color
ornamental, haybales, meadows, agricultural

Time of Greatest Risk


Geographical Distribution

Onions distribution - United States

Related Species


Allium spp.

Bulb Onion, Common Onion, Garlic
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Allium spp. are perennial bulb plants that are found worldwide as wild weeds or cultivated crops. There are over 400 different species of Allium, all of which possess the strong-smelling bulb smell when it is crushed. It has long, flat or tubular leaves and white, pink or purple flowers.

Toxic Components in Onion Plants

Alliumspp. contain N-propyl sulfide, allyl disulfide, and methyl disulfide.These compounds are toxic to horses if ingested in large enough quantities, causing oxidative damage to red blood cells. The amount of the chemical present in the plant depends on the species, time of year, and growing conditions.