The symptoms of headache and nausea in the afternoon are mainly caused by insufficient blood supply to the cerebral arteries, cold, cold or infection, and migraine, as follows: 1.Insufficient blood supply to the cerebral arteries: under normal circumstances, blood pressure is low in the morning and high in the afternoon. The common clinical symptoms are headache, nausea, vomiting, nasal congestion, runny nose, etc.; 3. Migraine: It is a kind of vascular fluctuation headache, more common in young female patients, acute recurrence of migraine induced by excessive mental tension, exertion, insomnia, headache and nausea can occur, usually should not stay up late, avoid getting cold.