The study aimed to identify and characterise changes occurring in the vertebral end-plate on MRI following uncomplicated lumbar discography. MRI was performed immediately before and within 2 h after uncomplicated lumbar discography in 20 consecutive patients undergoing the study as a precursor to possible spinal fusion. Of these, seven patients underwent a further MRI study at a mean of 72 days after discography (range 19-183 days). The MRI scans were assessed for the presence of any changes in the end-plates prior to and following discography. End-plate changes were identified in eight patients (40%) prior to discography. No new changes in end-plate signal intensity (SI) were identified in either the immediate or delayed MRI studies. The study suggests that any changes occurring in the vertebral end-plate following discography should be considered due to infectious discitis. There is no support for the concept of chemical discitis, chemical irritation of bone or microfracture of subchondral trabeculae as a cause of pain at discography.