A viral infection is caused by a virus and is often the cause of minor illness, such as a cold or the stomach flu. A viral infection usually causes many different symptoms that often come on quickly (over hours to a day or two) without prior illness.

Viral infections that cause minor illnesses are usually not serious and go away without medical treatment. Home treatment can relieve the symptoms of colds and stomach flu and prevent problems, such as dehydration. Antibiotics are not used to treat a viral illness and will not help cure a viral illness.

Some immunizations can prevent viral infections, including influenza (flu), chickenpox, and measles. Good hygiene and avoiding close contact with sick people can also help prevent infection.