The bruising that occurs after a blood draw from the wrist is caused by bleeding from the blood vessels that were drawn and bruised under the skin. This is mainly due to the fact that the patient did not apply pressure to the eye of the needle after the blood was drawn. In this case, the bleeding is not effectively stopped, so it can lead to bleeding in the bleeding vessel and cause bruising around it. In addition, it is also possible that abnormalities in the coagulation function of the patient’s body, such as abnormalities in the five blood clotting categories or low platelet counts, can cause this failure to stop bleeding at the eye of the needle. This is also a bruising condition caused by bleeding from the blood vessels under the skin. The patient is advised to apply prolonged local pressure to effectively stop the bleeding. If bruising is present, it is recommended that the patient should be treated with a local blood-boosting treatment. For example, applying Yunnan Baiyao cream to activate the blood can effectively improve these bruises.