Toxicity to pets

Flax seed and stalks hold cyanide-containing compounds and enzymes. When the plant material is chewed or damaged (e.g., frost, crushing) free cyanide can be released triggering cyanide poisoning when ingested. Cyanide reduces the body’s ability to process oxygen at a cellular level resulting in clinical signs including vomiting, drooling, gasping, collapse, seizure, and death. Livestock are at risk for flax poisoning.

Linseed oil from cold-pressed flax seed does not cause cyanide poisoning but can cause colic in horses if fed in large volumes.