Hay fever, also known as chytridiomycosis, is caused by the patient’s allergy to plant pollen, which mainly manifests as nasal itching, continuous sneezing episodes, large amounts of clear water-like nasal discharge and nasal obstruction; it can be accompanied by itchy eyes, tearing, conjunctival congestion and wheezing; it can also lead to skin itching and rash. The onset of pollen allergy is seasonal, with trees (elm, poplar, willow, cypress, tsubaki, oak, mulberry, ash, walnut) dominating the onset in spring, mostly from March to June; allergic pollen in summer mainly comes from forage and grasses (corn, sorghum, wheat, sedge, quinoa, amaranth, chrysanthemum, legume), mostly from May to August; in autumn, weed or atractylous pollen (Artemisia spp. Pollen, grass pollen, groundnut, sunflower, cannabis, castor) sensitized the most, about August-October onset, the three can overlap each other, they are wind-borne pollination by the wind. Preventive measures are the following: 1, off-site to avoid pollen contact, such as the northern autumn hay fever patients to live in the south in February. 2, pollen season as much as possible to reduce going out, especially dry and windy weather, flowers and plants in the mountains or grasslands. 3. If you go out, wear long-sleeved clothes, a pollen mask (which can be purchased in Japan or on regular websites such as Taobao), pollen glasses or a white transparent sarong over your head. For field work or spring excursions, it is best to bring some anti-allergy medication, such as Kestin, Kerratan, paracetamol, Benadryl, etc. 4. Wash your face, nasal cavity, eyes and other parts of your body that are sticky with pollen after going out, change your outerwear to reduce pollen exposure, and take a bath before going to bed to remove pollen from other parts of your body. 5. Close windows, doors and car windows during pollen season, open air conditioners with filtering function, install anti-pollen window screens, and do not hang clothes outside. 6.Apply pollen blockers to protect the nasal mucosa from exposure to pollen (Kemin). 7.Keep the air in the living room moist, apply air purifier or air conditioner filtration. 8.Adhere to a healthy lifestyle, maintain an optimistic and cheerful mood, and insist on swimming can reduce the symptoms. 9.Selective desensitization treatment at the end of the pollen season may be able to reduce the symptoms of hay fever in the coming year.