Black locust (Robinia pseudoacacia), often incorrectly referred to as acacia, is a deciduous tree in the bean family (Fabaceae) that can pose a toxic risk to horses. Native to parts of eastern North America, black locust grows rapidly and spreads...

Avocado toxicity in horses occurs when horses ingest leaves, fruit, stems, bark, or seeds from the avocado tree (Persea americana). Although avocado fruit is commonly consumed by humans, the plant contains compounds that can cause illness in several animal species,...

Allium plants are a bulb-forming species that include onions, garlic, leeks, shallots, and chives. Although these plants are common in human diets, they can pose a toxic risk to horses when consumed in sufficient amounts or repeatedly over time. Exposure...

Autumn crocus (Colchicum autumnale), also known as meadow saffron, is a highly toxic plant that can pose a serious risk to horses in pastures, hay fields, and contaminated forage. This small herbaceous perennial is native to Europe and parts of...

Bracken fern (Pteridium aquilinum) is a widespread toxic plant that can pose a serious risk to horses when consumed repeatedly in pasture or contaminated hay. This adaptable perennial fern grows throughout North America and many other regions, often establishing dense...

Blue-green algae poisoning in horses is a serious and potentially fatal toxicosis caused by cyanobacteria, microscopic aquatic organisms that can produce potent toxins in contaminated water sources. Harmful cyanobacterial blooms occur worldwide in freshwater and brackish water systems. Under favorable...