I never understood the appeal of fiddleheads, a harbinger of spring in Canada.

They look and taste like green turds.

The Toronto Star reports seven cases of illness associated with eating fiddleheads have been reported by residents to Toronto Public Health since the beginning of May, spokeswoman Kris Scheuer said. One case involved a family of four.

Raw or undercooked fiddleheads have been known to sporadically cause unpleasant symptoms of food poisoning since 1994, according to Health Canada.

The growing season for the ostrich fern sprouts is short, lasting from about the end of April till mid-June. The ferns grow in Ontario, Quebec and the Maritimes and are typically picked from the wild.

It’s not known why the spiralled veggies, nicknamed after their violinlike appearance, can make people ill. Scientists haven’t been able to trace any particular toxin to fiddleheads, according to Health Canada, so it’s up to chefs to cook them properly.

Health Canada recommends washing fiddleheads several times in cold water and removing as much of the papery, brown husk as possible. Then, steam them for 10 to 12 minutes, or boil for 15.

Get rid of the water afterward.