Oily hair may be caused by physiological factors or pathological factors, such as seborrheic dermatitis. 1. Physiological factors: If the daily life habits are bad, often eat barbecue, fried food, greasy food, etc., may cause the symptoms of greasy hair. If you don’t pay attention to hygiene and often don’t wash your hair, it will also aggravate the symptoms of greasy hair. Excessive use of hot water for daily bathing may cause damage to the normal barrier function of the scalp and stimulate the sebaceous glands, resulting in oily hair. 2. Pathological factors: If you suffer from seborrheic dermatitis, it will produce the symptoms of scalp greasiness, manifested as hair oil. In addition, there are endocrine disorders such as polycystic ovary syndrome can cause the body androgen abnormally high, resulting in sebaceous glands secretion, can also cause hair oil. If your hair is oily, it is recommended that you adjust your lifestyle, clean your hair in a timely manner, and if abnormalities occur, seek medical attention in a timely manner and follow the doctor’s instructions for symptomatic intervention.