Although fiddleheads contain carcinogenic substances, but a small amount and occasional consumption does not cause cancer, and the presence of carcinogenic substances does not necessarily lead to cancer. Fern mainly contains a kind of carcinogenic substance called protoferanoside, which exists in all parts of fern, and is higher in the young part of fern. Long-term consumption of large amounts of protoferanoside will increase the chances of developing esophageal cancer, but it needs to accumulate over the years to cause cancer. Although fiddleheads contain carcinogenic substances, consumption of carcinogenic substances does not necessarily lead to cancer, and issues such as consumption amount and preparation methods must be considered. The carcinogenic substances in fiddleheads are water-soluble, and the content is higher in the young part of fiddleheads, so you can consume only the part of fiddlehead stems, wash them with water before making them, and reduce the content of the original fern glycosides in fiddleheads by boiling them in water. Occasional consumption of boiled fern will not cause greater impact, but cannot be consumed in large quantities for a long time, and avoid eating pickled fern, especially for people with weak spleen and stomach, which should be consumed with caution. Cancer is a complex and slow process, which does not occur with the intake of a single food. You should eat less spicy, stimulating and fried food, and ensure a balanced diet and regular work and rest.