In clinical practice, we often encounter such a situation: many tumor patients and their family members consult medical personnel about the contraindication of hair products, some of them are doubtful about the doctors’ answers and explanations, and some of them even respect all hair products. So, can tumor patients eat hairy food or not? This question not only confuses many patients and their families, but also makes medical personnel often find it difficult to answer. In fact, hairy food is only a folk saying, which has not been recognized by modern science. Therefore, its exact definition cannot be found in authoritative medical textbooks and journals. The so-called hairy things, mainly refers to certain foods that can aggravate the disease or induce disease attacks, mainly including: fish, carp, eel, ark, clams, crabs, shrimp and sea cucumber, etc., animal meat, dog meat, donkey meat, horse meat and old hen meat, and vegetables such as leeks, celery, parsley and fennel. Nowadays, it seems that some of the hair products are related to allergic diseases, such as asthma and urticaria, while some are related to sores and swellings. Tumor patients, especially those in advanced stage, are prone to malnutrition and even cachexia (a state of severe wasting, weakness, anemia and general failure of the body). There are two reasons for this: firstly, the “crazy growth” of tumor tissues consumes a lot of nutrition, on the other hand, the fever, bleeding, infection, pain and other conditions combined with tumor and the toxic substances produced by tumor often make patients lose their appetite and lead to the reduction of energy intake; secondly, tumor can cause incomplete glucose metabolism and increase of nutrient metabolism. Increased metabolism of decomposition. This condition not only greatly reduces the patient’s resistance, making the tumor have more chances of metastasis and recurrence; but also may make the patient unable to tolerate surgery, radiotherapy and chemotherapy, and force the interruption of tumor treatment. From the perspective of modern pathology, tumor is neither an allergic disease nor a sore and swelling poison in the traditional sense, which is not related to the concept of hair products; nor can hair products cause metastasis and recurrence of tumor. From the perspective of modern nutrition, hair products, which are rejected by many patients, are mostly rich in high protein and vitamins, which are precisely excellent foods for them; hair products can not only ensure the nutrients needed by the organism, but also increase its immunity and disease resistance. From the perspective of clinical practice for many years, we have not yet seen any example of tumor metastasis and recurrence caused by eating certain foods, nor have we seen such reports in official journals and academic papers at home and abroad. Therefore, we believe that tumor patients not only can eat hairy foods, but also should eat more of them. However, it is advocated to forbid eating phosphorus-free fish and dog and mutton during taking herbal medicine.