The use of raw onion fumigation to relieve nasal congestion is a folk remedy. The principle is mainly to use volatile sulfides in onions (such as allicin, etc.) to stimulate the nasal mucosa and promote the discharge of secretions, thereby temporarily relieving nasal congestion. The following are the operation methods and precautions： --- ###**Operation steps** 1. **Prepare materials** -1 fresh onion (either white onion or purple onion) -Knives, cutting boards -Small bowl or plate -Hot water (optional, used to enhance the steam effect) 2. **Processing onions** - Peel the onion and chop it or cut it into thin slices to destroy the cell structure of the onion to release volatile components. 3. **Fumigation method** -**Direct inhalation method**: Put the chopped onion in a bowl with your head about 20-30 cm away from the bowl, take a deep breath with your mouth and nose, and inhale the pungent smell of onion volatilization for 5-10 minutes. -**Hot steam assisted method**: Put the chopped onion in a large bowl, pour a small amount of hot water (about 50℃-60℃), and diffuse volatile substances with the help of water vapor. Keep your head down at a safe distance (to avoid burns), cover your head and bowl with a towel, and breathe slowly for 5 minutes. --- ###**Precautions** 1. **Avoid direct contact** - Onion juice may irritate the eyes or skin. Wash your hands after operation and avoid rubbing your eyes. -Keep a proper distance during fumigation to avoid excessive irritation causing cough or discomfort. 2. **Applicable population** -Only suitable for mild nasal congestion (such as colds or early allergies), severe nasal congestion (such as sinusitis, nasal polyps) requires medical attention. -Use with caution in children, pregnant women, people with asthma or sensitive respiratory tract, which may induce cramps or allergies. 3. **Alternative** -If you are sensitive to onions, replace them with hot water vapor (add a small amount of mint or eucalyptus oil), or use saline to rinse the nasal cavity. 4. **Effect limitations** -This method only has a temporary relief effect. If nasal congestion lasts for more than 3 days and is accompanied by fever or pus, it is recommended to seek medical attention in time. --- ###**Scientific basis reference** The sulfides in onions have certain antibacterial and mucosal stimulating effects, but there are no sufficient studies to prove their direct treatment of nasal congestion. It is recommended to combine safer methods such as adequate drinking water and keeping the air moist (such as humidifiers) to assist in relief. I hope the above methods can help you, but you need to be cautious about health problems. Please consult your doctor if necessary!