Cats can eat spider plants safely as they are non-toxic to cats. However, eating large amounts of spider plants may cause mild gastrointestinal upset such as vomiting or diarrhea. The plant is mildly hallucinogenic to cats, which may attract them to nibble on it, but it does not cause serious poisoning. It is advisable to monitor cats if they eat spider plants and try to keep the plants out of reach to prevent excessive ingestion and potential stomach upset.