Flu and cold are not the same disease, even caused by different viruses.
Although they have similar symptoms, the flu is more severe than the cold. Usually, it starts with a high fever, followed by muscle pain, sore throat, headache, runny nose and dry cough. The less complicated flu usually gets better within 5 days of the onset of symptoms. However, in some cases the picture may extend for more than a week.
The cold, which is also a respiratory disease, has less severe and less lasting symptoms (usually between two and four days). They include cough, nasal congestion, runny nose, body pain and mild sore throat.
In the cold, fever is less common, while in flu fever is the most important symptom and lasts around three days.
Many people confuse flu with the cold because they have similar symptoms.
The flu is caused by the influenza virus, while the cold is caused by several types of viruses, including rhinovirus, which is one of the most common.