Historical QOD 11/12/08: What are the poisonous constituents of horse chestnuts?
Ingestion of horsechestnut has been associated with GI illness, esculins in the saponin fraction of the horse chestnut are thought to be responsible by increasing GIT in a dose dependent manner.
Matsuda H, Li Y, Yoshikawa M. Effects of escins Ia, Ib, IIa, and IIb from horse chestnuts on gastrointestinal transit and ileus in mice. Bioorg Med Chem. 1999 Aug;7(8):1737-41. doi: 10.1016/s0968-0896(99)00100-5. PMID: 10482465.