Common cold or cold or coryza is a viral infection of the upper respiratory tract that primarily attacks the mucous membranes of the nose and throat, but can also appear in the lungs. The common cold has no precise scientific and medical definition (it has only as much relation to cold as that pathogens are seasonally more active in winter). Its most common pathogen is rhinovirus, but more than two hundred different viruses can cause it and sometimes bacterial infection can also worsen the symptoms. The common cold is often confused with the much more severe influenza. The common cold is the most frequent type of infection among humans.

Symptoms include cough, sore throat, runny nose and fever, depending on the severity and extent. Symptoms usually disappear after seven to ten days, but some may persist for up to three weeks.

Upper respiratory infections are categorised according to the areas of the body most affected. Symptoms are not caused by tissue damage from viruses, but by the immune system's response to infection.

There is no cure for the common cold, but symptoms can be treated. Adults get a cold on average two to three times per year. Among children, the average is six to twelve colds per year. The primary method of preventing infection is frequent handwashing, and there is also evidence that wearing a face mask can be an effective protective method.
Source: https://hu.wikipedia.org/wiki/Megfázás