the common cold is caused by viruses. it spreads easily, so it is very infectious. the symptoms are mostly in the upper respiratory system. its damage is mostly felt in the nose and throat. the symptoms include coughs, painful throat, runny nose and fever. these symptoms usually last seven to ten days, but sometimes up to three weeks. "over two hundred different viruses can cause the common cold": that is why the details vary so much. rhinoviruses are the most common cause.