Air conditioners blowing directly on the head is more harmful, especially in summer, through the air conditioning cooling, if blowing directly on the head. First of all, it will cause symptoms such as cold and flu. Because the air conditioning cooling wind is relatively hard, relatively cool, blowing directly is easy to cause cold, headache, fever, nasal congestion, runny nose and other symptoms of the cold. Secondly, it is easy to cause headache disease, often with air conditioning blowing directly on the head, it is easy to cause neurological headache, and later also easy to appear afraid of the wind, fear of cold symptoms. Finally, blowing directly against the head is also likely to cause facial paralysis, which is the medical term for facial nerve palsy, the appearance of crooked eyes, cheek leakage, incomplete eyelid closure and other symptoms.