This paper was written into condsideration records about the definition of "Ong-Jeo", the difference between "Ong" and "Jeo", the Western medical approach to "Ong-Jeo", and the etiology and pathologic mechanism of "Ong-Jeo". After this study, I report the following results from it. 1. "Ong" is an acute diapyesis disease which is found is in our skin and muscle and flesh. The chrateristics of this disease is that the affacted site is shine, no head, and the size is 3-4 chon. The prossess of the diesease shows that it is very quick, and very easily swell, and becomes pus easily, easily become to ulcer, easily converge. But this don't damage to the muscle and bone. 2. "Jeo" is the disease which damages bone-skeleton, muscle and flesh, and even destroy the stationary tissue. Jeo can be divided into two. One is called "Yudujeo" and it is acute diapydesis disease. The characteriscs of this disease is the miliary abscess, swell, has fever, and has an ache which is feeled spaned. And this is diffused into periphrey tissue and is diffused into deep site. After the ulcer, this becomes to shape the cellula. The size is more than 3-4 chon and this disease goes into chuk if this is serious. The other one is called "Mudujeo" and this disease is the ulcerative one in our joint and skeleton. The characteristic of this disease shows that the color of skin be not changed, and swell diffusely, and is not easily vanished, not easily becomes ulcerative, and not easily becomes converged. 3. "Ong-Jeo" is caused by the bacteriunm named by the "Golden and Yeollw Staphylococcus" in the Western medicine. "Ong" can be applicable to the carbuncle, acute diapyesis lymphadenitis, and some of cellulitis. "Jeo" can belong to cellulitis, and Mudujeo can belong to suppurative arthritis, suppurative osteomyelitis, tuberculous arthritis and osteomyelitis, and tuberculous lymphadenitis. 4. The etiologies of "Ong-Jeo" can be divided three, which are internal, external and other etiology which can not be clasiffied by two etiologies above. The internal etiology is seven emotion, and the external etiology is the six eumsa, unki, chunhang and so on. Other etiology is inadequate absorption of food, and excessive bang-sa. 5. The etiology of "Ong" is suppurative one which is choked between our skin and muscle and flesh, and is congested, become to hot, and finally erodes the muscle and flesh because of the inbalance of cirrculation in the enegy and blood. "Jeo" is the same as the Ong, but this is the suppurative disease which damages the muscle, flesh, and skeleton, and even damages into five Zang, the internal intestine.