#17 Plant Leaves
Cats are curious creatures and like to chew on alien foods. However, this sport does not prove harmless every time. Leaves of some plants such as rhubarb, tomato, and carrots, among others, can have irritating effects on cats and may even lead to poisoning.
There is a long list of plants that are potentially harmful not only for cats but for humans as well. For instance, the Daffodil bulb can cause serious troubles when ingested, like diarrhoea, vomiting, nausea and abdominal pain.