According to its clinical manifestations, the disease belongs to the categories of "zang du" (visceral toxin), "chang feng" (intestinal wind), "chang xun" (intestinal fungus) and "ji ju" (masses) in traditional Chinese medicine. The pathogenesis of this disease is that the constitutional asthenic spleen and kidney or improper diet causes deficiency of the spleen and stomach; moreover, accumulation of toxic heat, fire and dampness flow downwards to the intestines, and in the course of time, the mass is formed. Damp heat, toxic heat and blood stagnation are the secondary aspect of the disease; spleen deficiency, kidney deficiency and deficiency of healthy qi are the principal aspect. However, the principal and secondary aspects interact as both cause and effect and most of the cases are characterized by principal deficiency and secondary excess.