Cold, known to be associated with the winter season, water element, Yin, and Kidneys, is a common sickness caused by external exposure to cold weather or measures, such as strong air conditioning. This invasion can result in superficial symptoms, such as muscle stiffness and joint pain, or deeper issues in organs, such as infertility in the uterus. Cold impairs Yang, coagulates Qi, blood and body fluids, and contracts muscles and tendons. Endogenous cold is caused by a deficiency of Yang Qi in the kidney, spleen, or heart and manifests as weakness, low energy, and poor circulation. To recover from a cold invasion, warming and dispersing foods and herbs are necessary.