According to North Carolina State University, hyacinth (Hyacinthus orientalis) and Narcissus species, which include narcissus, jonquil and daffodil, all cause nausea, vomiting and diarrhea. Hyacinth can be toxic in large quantities. Narcissus species also cause trembling, convulsions and salivation if ingested and can be fatal. Contact with the bulbs of Narcissus species can cause skin irritation. According to Texas A&M University, elephant ear (Colocasia spp) can cause irritation and intense burning of the tongue and mouth. It is not fatal on its own, but can cause the tongue to swell enough to block airways.
The following plant bulbs cause varying degrees of stomach upset if ingested: tulip (Tulipa spp); wild garlic and meadow garlic; Star of Bethlehem (Ornithogalum umbellatum); amaryllis (Amaryllis belladonna); snowdrops (Galanthus nivalis); spider lily, sea daffodil and basket flower (Hymenocallis spp); Crinum species; blood lily (Scadoxus multiflorus); iris species; and crocus species. Star of Bethlehem and tulips can also cause irritation if they contact skin.
Gardeners should take precautions with bulbs, including wearing gloves, storing bulbs out of reach of children and pets and taking care to ensure that any bulb destined for the dinner table is actually edible.