Are buckeyes poisonous?

The seeds, leaves and sprouts of the buckeye, or horse chestnut, are all poisonous to livestock and humans when consumed. The sprouts and seeds, which contain the highest concentrations of the chemical aesculin, are the most toxic parts of the plant.

After ingestion, high concentrations of aesculin build up in the bloodstream and negatively impact the central nervous system, leading to symptoms such as vomiting, trembling and a staggering gait. However, buckeye seeds are also high in protein and were historically used as a food source by certain Native American tribes, who boiled and leached the seeds to remove the toxins.