The hardening of the blood vessels after an indwelling needle may be caused by phlebitis in the patient. Depending on the degree of the patient’s condition, general treatment, drug treatment and so on can be chosen. Phlebitis is mainly caused by the damage of the blood vessel wall caused by the indwelling needle and the stimulation of the blood vessel by the highly concentrated drug solution infused into the blood vessel, which results in the local inflammatory reaction of the blood vessel and leads to the hardening of the blood vessel. When the hardening of blood vessels, the general treatment is to pull out the indwelling needle, and at the same time to the puncture blood vessels for localized hot compresses; medication can be used under the guidance of the doctor, such as the use of heptaphyllum saponin sodium gel to improve the symptoms of blood vessels external application. In severe cases, anticoagulant therapy such as rivaroxaban should be taken under doctor’s supervision, otherwise life-threatening complications such as pulmonary embolism may occur. If symptoms are not relieved after general treatment, consult a doctor for standardized treatment.