After washing the head or very oily may be due to seborrheic dermatitis, ringworm, shampoo products improper selection, dietary factors and other factors. 1. seborrheic dermatitis: seborrheic dermatitis patients can appear scalp sebaceous gland secretion, sebum secretion increased, resulting in hair greasy symptoms, accompanied by dandruff, hair loss, itching and other symptoms. 2. Tinea capitis: due to the infectious disease caused by ringworm bacteria, resulting in scalp sebaceous gland secretion dysfunction, at the same time, ringworm will appear oozing phenomenon, aggravate the situation of hair oil. 3. improper selection of shampoo products: oily shampoo products can lead to hair easily greasy symptoms, it is recommended that patients with oily hair use shampoos with strong oil removal effect, so as not to aggravate the symptoms of hair oil. 4. Dietary factors: like to eat greasy high sugar food people, the secretion of oil will be relatively more, and lead to the emergence of hair easily greasy symptoms. After washing the head or very oily may also be caused by other factors, adjust the daily routine and hair care habits after the patient still did not see improvement, it is recommended that timely to the regular medical institutions, in order to clarify the cause of the disease after targeted treatment.