They are pathological products caused by disturbance in water metabolism.  Phlegm retention is a combined term for phlegm and fluid retention.  In a narrow sense, it refers to sputum that is visible.  The dense, viscid and thicker dampness is called phlegm and the thinner one named retained fluid.

In a broad sense, it includes not only the tangible sputum but also the shapeless one.  The latter is formed by accumulation of dampness and qi, known as the invisible fluid, such as subcutaneous nodule, medullitis, scrofula, goiter, etc.  Such symptoms as dizziness, nausea, vomiting, chest oppression, palpitation, and manic-depressive psychosis and coma believed to be caused by it.  In these disorders no expectoration of  sputum is found, but if we adopt the methods of resolving, eliminating phlegm with medicinal herbs, there are satisfactory results.

Stagnation or stasis of blood impeded blood circulation and implies blood circulation and triggers dysfunction of the zang-fu organs.  It is often caused by qi deficiency, qi stagnation, or cold in blood, or internal hemorrhage due to excessive heat or traumatic injury, and it accumulates in a local area.  This is called blood stasis, which disturbs the circulation of qi and blood, and produces pain.