A method of augmenting an intervertebral disc nucleus by injecting or otherwise adding to a disc nucleus a plurality of particles of natural, collagen-rich tissue. The mean particle size of the pieces of natural, collagen-rich tissue may be between 0.25 mm and 1.0 mm. The particles may be dehydrated before implantation, and rehydrated after implantation, or they may be implanted in a "wet" state--such as a slurry or gel. Radiocontrast materials may be included to enhance imaging of the injected material. Other additives may include analgesics, antibiotics, proteoglycans, growth factors, stem cells, and/or other cells effective to promote healing and/or proper disc function.