Snake plants (Sansevieria trifasciata) are indeed poisonous to cats. All parts of the plant contain saponins, a toxin that can cause illness in cats if ingested by chewing on the leaves. Common symptoms of snake plant poisoning in cats include nausea, vomiting, diarrhea, lethargy, loss of appetite, drooling, and swelling of the mouth or throat. Most cases result in mild to moderate gastrointestinal upset, but it is important to contact a veterinarian promptly if ingestion is suspected to ensure the cat receives proper care.