The main reasons why people tend to catch colds in spring are the sudden change in climate, exposure to cold, and the increase in the number of people’s activities, which leads to an increase in the probability of viral/bacterial infections. Colds are also categorized into common colds and influenza, with the former being the most common. 1. Common colds: caused by viral infections (rhinovirus, adenovirus, etc.), large temperature changes in spring (easy to get cold), easy to work, etc., reduce the local defense function of the respiratory tract, the body’s immune function decreases, leading to infection. 2. Influenza: the northern part of the spring/winter is more frequent, the southern part of the year can be popular, the crowd is generally easy to infect, the pathogen (various types of RNA influenza virus) mainly through contact and air droplet transmission (human-to-human transmission), resulting in influenza infection. The spread of influenza is mainly influenced by the virulence/transmission strength of the virus, and more intensive crowd activity after spring may be a major susceptibility factor. Prevention should try to avoid going to places where people gather, such as movie theaters and shopping malls, or wearing a mask can reduce the likelihood of infection.