Cupping is a method used in Tradtional Chinese Medicine for treating disease that is caused by local congestion whereby a partial vacuum is created in a cupping jar, sometimes used  with heat or a tens-like pulsing sensation. Applied directly to the skin; the underlying tissue is drawn up into the jar forming an area of blood stasis. The result can appear to bruise the area, or turn it a bright red. Depending on the amount of dark red or purple blood drawn to the surface indicates the degree of stagnation. The darker the area; the more it is a sign of stagnation, which most often is the amount of toxins in the blood. In ancient times, animal horns and bamboo jars were used, principally to drain pustulating sores.