Unconscious head shaking is mostly seen in primary tremor, also known as idiopathic tremor. Primary tremor is generally related to genetics and is a benign movement disorder disease, manifesting only as tremor, clinically manifested mainly as involuntary tremor of the upper and lower extremities or head and face, in addition, some other factors such as caffeine stimulation, calcium deficiency, Parkinson’s disease, hyperthyroidism, etc., can also lead to unconscious head shaking. 1, caffeine stimulation: some people, after drinking excitatory beverages such as coffee, tea, cola, etc., will have head tremor, manifested as unconscious head shaking, this and the intake of caffeine has a certain relationship, in addition to being more sensitive to caffeine; 2, calcium deficiency: common in infants and young children, due to the need for more calcium, but insufficient supplementation, will lead to lower serum calcium, so that neuromuscular excitability increased, leading to involuntary head tremor, shaking; 3, Parkinson’s disease: Parkinson’s disease is a common elderly neurological degenerative disease, mainly manifested as unconscious head shaking, but also accompanied by slow movement, muscle ankylosis, abnormal posture and gait, etc.; 4, hyperthyroidism: caused by excessive production of thyroid hormones, which can cause subtle tremors or shaking of the head and upper limbs, etc. If the tremor is idiopathic and does not affect life, you can consider observing it first. If the symptoms are more obvious, it is recommended to consult a neurologist and ask the doctor to prescribe the corresponding medication, or if it is caused by other factors, you need to actively treat the primary disease so as to help control the symptoms.