Lilies
Members of the Lilium spp. are considered to be highly toxic to cats. While the poisonous component has not yet been identified, it is clear that with even ingestions of very small amounts of the plant, severe kidney damage could result.
Marijuana
Ingestion of Cannabis sativa by companion animals can result in depression of the central nervous system and incoordination, as well as vomiting, diarrhea, drooling, increased heart rate, and even seizures and coma.