Hibiscus is poisonous to cats. A cat that ingests hibiscus experiences nausea, vomiting and diarrhea. It often refuses to eat, and it may even develop anorexia.
If a cat ingests any part of the plant, it should be taken to the veterinarian immediately, even if there are no symptoms of poisoning. Hibiscus is also poisonous to dogs and horses, causing the same symptoms.
The only way to keep a pet safe from poisoning is by not having such plants. If a pet owner has a poisonous plant in the home, it should be kept out of reach of the animals.