Philodendron
Philodendrons don’t require a lot of TLC, which is why they’re commonly found in people’s backyards around the USA. Unfortunately, their leaves are toxic and contain calcium oxalate, which inflames the mucous membranes of the mouth and throat if accidentally ingested. It’s worse if small children or pets accidentally ingest the leaves, and the more leaves they eat, the more toxic it is. Rarely, if the throat swells too much, it may be difficult to breathe (Queensland Government).