Acute pyogenic vertebral spondylodiscitis（APVS）is of special interest to physicians because it often results in acute neurological deterioration and requires a combination of adequate surgical and conservative treatment. The aim of the current study is to evaluate this disease, including its diagnosis and treatment. The subjects of this study were 4 patients with APVS who were treated at the Nagami Clinic in Unnan, Shimane, Japan, from 2000 to 2008. All 4 patients had underlying diseases such as diabetes mellitus and liver cirrhosis. The main causative organism was recognized only in case 3: Clostridium perfringens and Escherichia coli. Most infections were localized in the lumbar spine, as shown by Magnetic Resonance Imaging（MRI）. None of the patients presented with neurological deficits on admission on account of a delay in diagnosis. Clinically, all 4 patients had severe lumbar pain and gait disturbance besides high-grade fever. Of the 4, only one patient with rapidly progressing acute respiratory dysfunction as well as severe septicemia developed multiple organ failure and underwent emergent operation. The other 3 patients were treated with immobilization and intravenous antibiotic drugs. All cases were treated with broad-spectrum antibiotic drugs delivered intravenously for at least 14 days, followed by orally administered antibiotics for more than 14 days. From an etiological viewpoint, it is possible that bacterial infection into the blood flow as a result of surgery resulted in the occurrence of APVS in 2 of the 4 cases. On the other hand, the pathogenesis of the remaining 2 cases was unknown, but it was speculated that immunoreaction to bacterial invasion was disturbed or feeble in the patients due to their having experienced diabetes mellitus or liver cirrhosis for a long time. Major complications were not recognized, mainly due to long-term antibiotic therapy. APVS is very rare, and it is fatal disease if the diagnosis is delayed. Thus, APVS must be suspected and taken into consideration first if a patient with severe lumbar pain and high-grade fever is encountered. Due to the factors explained above, diagnosing patients with acute lumbar pain presents several challenges.