Multidistrict litigation is a legal procedure in United States federal courts in which lawsuits involving similar issues (common issues of fact) are consolidated in one court (called the MDL court) for the purpose of convenience and efficiency in pretrial matters, such as discovery. These lawsuits are generally returned to their original federal district courts for trial. Claims that are often the subject of multidistrict litigation are product liability claims against pharmaceutical companies, securities fraud cases, and airplane crashes.

In Ohio, as in other states, multidistrict litigation (MDL) is a federal legal procedure that consolidates multiple lawsuits involving common factual issues to improve efficiency and convenience during pretrial proceedings. This process is governed by federal law, specifically 28 U.S.C. § 1407, which allows for civil actions in different districts with one or more common questions of fact to be transferred to any district for coordinated or consolidated pretrial proceedings. The Judicial Panel on Multidistrict Litigation (JPML) decides whether cases should be consolidated under MDL and to which court they should be transferred. While pretrial activities such as discovery and motions are centralized, the individual cases typically return to their original jurisdictions for trial unless they are settled or dismissed during the MDL process. MDLs are commonly used in Ohio for complex cases like product liability suits, including those against pharmaceutical companies, as well as securities fraud cases and major accident litigation such as airplane crashes.