A Study in Participants With Diabetic Peripheral Neuropathic Pain in China

Inclusion Criteria: * Present with pain due to bilateral peripheral neuropathy * Participants must have pain caused by Type 1 or Type 2 diabetes mellitus * Pain must begin in the feet with relatively symmetrical onset * Daily pain should be present for at least 6 months * Diagnosis must be confirmed by a score of at least 3 on the Michigan Neuropathy Screening Inventory (MNSI) * Females must test negative for a serum pregnancy test at Screening. Females of child-bearing potential (who are not surgically sterilized and between menarche and 1 year postmenopause) must agree to use a medically acceptable and reliable means of birth control, during the study and for 1 month following the last study dose. * Stable glycemic control as assessed by a physician investigator and a glycosylated hemoglobin (HbA1c) \<12% before randomization * Score of greater than or equal to 4 on the Brief Pain Inventory (BPI) 24-hour average pain item at Screening. * Full completion of the daily diaries for at least 80% of the days between the second and third time you come to the hospital (Screening). Exclusion Criteria: * Currently enrolled in, or discontinued within the last 30 days from, a clinical trial involving an investigational drug or device or off-label use of a drug or device, or concurrently enrolled in any other type of medical research judged not to be scientifically or medically compatible with this study * Current (less than or equal to 1 year) Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) Axis I diagnosis of major depressive disorder, dysthymia, anxiety disorders (excluding phobias), alcohol or eating disorders as determined by the Mini-International Neuropsychiatric Interview (MINI) or a previous diagnosis * DSM-IV diagnosis of mania, bipolar disorder, or psychosis determined either by participant history or by diagnosis using specific MNSI modules * Serious or unstable cardiovascular, hepatic, renal, respiratory, or hematologic illness, symptomatic peripheral vascular disease, or other medical condition or psychological conditions that in the opinion of investigator would compromise participation or be likely to lead to hospitalization during the course of the study. * At Screening alanine transaminase (ALT) greater than 2 times upper limit of normal (ULN), based on central laboratory reference ranges times ULN, based on central laboratory reference ranges * Prior renal transplant, current renal dialysis, or serum creatinine laboratory value \>1.5 times ULN, based on central laboratory reference ranges at Screening. * Historical exposure to drugs known to cause neuropathy, or a history of a medical condition, including pernicious anemia and hypothyroidism, that could have been responsible for neuropathy * Pain that cannot be clearly differentiated from or conditions that interfere with the assessment of the diabetic neuropathy pain. Examples of painful conditions that could be confused with diabetic neuropathy pain include peripheral vascular disease, neurological disorders unrelated to diabetic neuropathy, skin condition in the area of the neuropathy that could alter sensation, other painful conditions * Participants who have previously completed or withdrawn from this study or have been previously treated with duloxetine, including participants who participated in study F1J-MC-HMEQ (NCT00408993), even those in the placebo arm * Participants taking excluded medications that cannot be stopped at Screening * Treatment with a monoamine oxidase inhibitor (MAOI) or fluoxetine within 30 days of the third Screening * Participants with a positive Hepatitis B surface antigen and/or Hepatitis C antibody are to be excluded if they have any of the following: * Hepatic dysfunction as determined by the investigator or * Clinical manifestations of liver disease within the previous year such as unexplained pruritus, unexplained dark urine, jaundice, unexplained right upper quadrant tenderness, unexplained "flu-like" symptoms or * Aspartate transaminase (AST), ALT, or bilirubin above the normal reference range.