Like most plants grown from bulbs, daffodils are toxic. The bulb is the most dangerous part of the plant, so if you are planting some of these lovely yellow flowers, be sure to keep the bulbs locked up tight. They may look like a chew toy or ball for a playful pet. If eaten in large amounts, daffodils can cause low blood pressure and heart problems, as well as convulsions. Smaller tastes are more likely to result in vomiting, drooling and diarrhea.