Whether a cold shoulder or back needs a plaster depends on its cause. As plasters can invigorate blood, reduce swelling and pain, soothe tendons and channels, warm the meridians and disperse cold, and dispel wind and dampness. Therefore, for coldness in the back of the shoulder caused by cervical spondylosis, plasters can promote blood vessel dilation and accelerate blood circulation, thus reducing inflammation and swelling. However, for other causes of cold shoulders and backs, such as low blood pressure and thyroid disorders, plasters are not very effective and patients should go to a specialist hospital for treatment under the guidance of a medical practitioner.