Are rhubarb leaves poisonous to worms and why?

Yes, rhubarb leaves are toxic to worms due to the presence of oxalic acid and anthraquinone glycosides, which can be harmful if ingested. These compounds can disrupt cellular processes and lead to poisoning in many organisms. While worms can tolerate some levels of certain toxins, the concentration in rhubarb leaves is generally too high for them to handle safely.