Thomas Yoo is a Los Angeles litigation attorney and leader of the firm's Product Liability Life Sciences Team. Mr. Yoo's practice includes a variety of product liability matters and commercial disputes. He has served in national, regional and trial counsel, and other strategic, roles on behalf of leading companies in numerous industries, including life sciences, manufacturing, financial services, real estate, transportation and private investment ventures.

Mr. Yoo handles a wide range of complex cases, negotiations and exposures, from prescription pharmaceuticals and medical devices to environmental toxic exposure matters, from mass torts involving thousands of cases to individual contract actions. He has in-depth experience in cross-border business disputes, federal multidistrict litigation (MDL) and statewide coordinations, class action defense and high-profile matters garnering national media attention.

In addition to crafting litigation and trial strategy, Mr. Yoo regularly handles complex scientific issues faced by his clients in life sciences and toxic tort litigations. From safety data in U.S. Food and Drug Administration (FDA)-reviewed randomized clinical trials to differential risk signals and covariate analyses in epidemiologic research and Environmental Protection Agency (EPA) evaluations, from clinical outcomes and medical causation issues to biologic mechanisms and laboratory biomarker studies, Mr. Yoo defends his clients with a comprehensive understanding of the scientific issues implicated in the litigation. Mr. Yoo has worked with leading scientists and medical doctors, and has handled the cross-examination and Daubert challenges of experts, in a variety of fields, including cardiology, neurology, oncology, epidemiology, gynecology, pulmonology, pharmacology, toxicology, hematology, metallurgy, vascular biology, rheumatology and pharmacokinetics.

In Legal 500 USA's annual national rankings of top law firms, Mr. Yoo is described as "an excellent strategist."

Product Liability And Consumer Class Action Litigation Matters

  • Defending class action litigation alleging antitrust violations with respect to development and marketing of anti-HIV medications 
  • National and trial counsel for Merck, Schering-Plough and Organon in defense of litigation involving prescription contraceptive product NuvaRing and allegations of thromboembolic injuries and wrongful death; litigation involved more than 4,000 claims nationwide, federal multidistrict litigation (MDL) in Missouri, statewide coordinations in New Jersey and California and various state court actions; won dismissal of all cases in the initial bellwether pool, leading to national settlement and resolution of litigation
  • Lead counsel for manufacturer of agrochemical products in product liability litigation alleging cancer risk from glyphosate herbicide products
  • Lead counsel for pharmaceutical client in litigation in multiple jurisdictions involving U.S. Food and Drug Administration (FDA)-approved hormonal implants
  • Defended pharmaceutical manufacturer in brain injury case in Bronx, N.Y., state court, involving 17-year-old plaintiff with pulmonary embolism, cardiac arrest and brain damage, allegedly from use of the client's prescription drug product; in the face of plaintiff's $27 million settlement demand, won dismissal on all causes of action
  • Defended pharmaceutical client in U.S. District Court for the District of Massachusetts in product liability case alleging stroke and permanent neurologic deficit, involving a $21 million plaintiff settlement demand; won dismissal on all causes of action
  • Lead counsel for biotech company concerning safety, remedial assessments, and regulatory counsel relating to product manufacturing issues involving FDA-approved cancer treatment
  • Defending insurer client in putative class action alleging wrongful denial of benefits under medical insurance plan
  • Defended supplement leader BSN in national class action alleging consumer fraud claims over several popular creatine and energy sports supplement products
  • Trial counsel for Lincoln Electric, Hobart and other leading manufacturers of welding electrodes in numerous wrongful death, mesothelioma and other personal injury asbestos actions throughout the western United States; did not lose or settle a single case in any jurisdiction in the six years defending these clients
  • Defense liaison counsel for Merck in California statewide litigation involving nearly 4,000 cases alleging heart attack and stroke injuries from use of prescription pain medication Vioxx
  • Defense counsel for pharmaceutical client in putative class actions brought by third-party payors over efficacy and safety of prescription medication
  • Won dismissal of "wrongful birth" product liability action alleging defect in long-acting contraceptive implant in U.S. District Court for the District of Maine, and successfully defended judgment in the First Circuit Court of Appeals
  • National counsel for commercial kitchen equipment manufacturer in asbestos product liability personal injury and wrongful death actions venued in jurisdictions across the country
  • Defense counsel for welding electrode manufacturers in toxic tort litigation alleging manganese-induced neurologic injuries from exposure to welding fumes; guest speaker before California industrial hygiene association

Commercial Litigation Matters

  • Represented investment client in breach of contract action involving farming and marketing of commercial table grapes in U.S. District Court for the Central District of California, resulting in successful recovery
  • Successfully defended Korean conglomerate, CJ Corp., in action alleging $30 million for breach of commercial distribution agreement and business torts involving line of cosmetics products
  • Defended the University of Southern California in alleged $100 million breach of contract and business torts action involving dental implants and clinical trial agreement; won summary adjudication on 11 of 13 causes of action, including Section 17200, and struck plaintiff's $100 million lost profits claim at trial
  • Lead counsel for a global investment client in breach of contract, fraud and environmental contamination action involving sale of commercial property in New Jersey state court, won dismissal in client's favor on all causes of action
  • Represented pharmaceutical client in breach of contract claim involving product manufacturing agreement 
  • Defended manufacturer of welding materials in numerous cases alleging economic loss from defective metallurgic properties in materials incorporated into high-rise seismic steel frame buildings throughout Los Angeles


  • UCLA School of Law, J.D.
  • University of California, Los Angeles, B.A.
Bar Admissions/Licenses
  • California
Court Admissions
  • U.S. Court of Appeals for the First Circuit
  • U.S. Court of Appeals for the Ninth Circuit
  • U.S. District Court for the Central District of California
  • U.S. District Court for the Eastern District of California
  • U.S. District Court for the Northern District of California
  • U.S. District Court for the Southern District of California
Honors & Awards
  • Diversity & The Bar, Leading Product Liability Lawyer 
  • Southern California Super Lawyers magazine, Class Action & Mass Torts Law 
  • Who's Who Legal – The International Who's Who of Product Liability Defense Lawyers 
  • Who's Who Legal – The International Who's Who of Life Sciences: Product Liability Lawyers
Spoken Languages
  • English
  • Korean