Hay fever is caused by an allergy to pollen, according to the NHS.
The allergic reaction is usually worse when pollen comes into contact with your mouth, nose, eyes or throat.
Hay fever symptoms include sneezing, coughing, watery eyes, headaches and itchy throats.
The Met Office has warned of “very high” pollen counts this week in some parts of the UK.
You can relieve your hay fever symptoms by lining your nostrils with petroleum jelly, or showering after going outside, the NHS said.
Putting petroleum jelly around your nostrils could trap pollen before it enters the body.
Pollen could also stick to your clothes after you’ve been outside.
If you go outside, you should change clothes and have a quick shower, it added.
Ideally, stay indoors as much as possible, and keep windows and doors shut.
Vacuum regularly and dust your home with a damp cloth.
“There’s currently no cure for hay fever and you can’t prevent it,” said the NHS.
“But, you can do things to ease your symptoms when the pollen count is high.
“Wear wraparound sunglasses to stop pollen getting into your eyes.
“Buy a pollen filter for the air vents in your car and a vacuum cleaner with a special HEPA filter.”
If you have hay fever, you should avoid spending too much time outdoors, or walking on grass, the NHS added.
Smoking could make your symptoms worse, while drying clothes outside can trap pollen in your laundry.
Speak to a pharmacist if you have hay fever.
They can advise you on the best treatments available, including antihistamine tablets or nasal sprays.
If your symptoms are getting worse, or if they don’t improve after taking medication, you should speak to a GP.
Your doctor could prescribe steroids to help reduce your hay fever symptoms.