Free radical generating substances, including fulvic acids, mycotoxins, Fe(II), etc attack chondrocytes, causing dedifferentiation. The dedifferentiated cells synthesize and secrete abnormal collagens rich in type I instead of the normal type II. These substances also directly attack collagens in the extracellular matrix. The abnormal collagens make the matrix change from hydroxyapatite crystallization inhibiting to promoting, and give crystals of low crystallinity, high aggregation and small size. This study leads to a new concept of the development of Kaschin-Beck's Disease (KBD).