According to WebMD, daffodils should not be eaten. Ingesting daffodils can cause a number of severe side effects, including chills, fainting, diarrhea and vomiting severe enough to require hospitalization.
Some people use daffodils in homeopathic medicines, including the stem, stalk and flower, but it is not advisable. In addition to the side effects, eating daffodils can also lead to brain disorders, swelling of the throat and mouth (leading to difficulty breathing) and lung collapse. Given the severity of the side effects, the plant can even lead to death. Sometimes the daffodil plant is confused with non-toxic Chinese chives used in cooking, so harvesters should be certain what plant they are gathering.