O’Melveny Worldwide

Houman Ehsan holds a JD, MD, and an MBA, a combination that allows him to focus his practice on the nexus of medicine, business, and the law. As an attorney–physician, he handles complex medical and scientific issues arising from products liability, toxic torts, healthcare litigation defense, healthcare due diligence, and healthcare financial arrangements. He also provides strategic counseling to smaller biotechnology and pharmaceutical companies related to novel therapeutics.  

He has extensive experience working with expert witnesses in products liability, toxic torts, and general healthcare litigation settings. And within O’Melveny, Houman himself is recognized as an in-house expert, called on to translate the intricacies of the healthcare and life-sciences industries into practical advice for fellow litigators.  

He counsels clients ranging from biopharmaceutical, to managed health care, to technology to energy and chemical manufacturing companies on a range of medical and scientific issues.

  • Leading the identification, selection, and preparation of dozens of medical and scientific experts for pharmaceutical clients facing mass torts in state and federal courts
  • Coordinating preparation, deposition, and motion practice challenging opposing experts’ opinions under California and federal law on behalf of pharmaceutical clients
  • Providing a tutorial to the bench on the key scientific concepts underlying mass torts cases in both state and federal courts during various “Science Day” presentations
  • Providing case-specific causation analysis for multiple major pharmaceutical companies in products liability actions in numerous federal and state courts
  • Performing internal investigation and risk assessment on behalf of large healthcare providers
  • Performing healthcare due diligence of pharmaceutical, biotechnology, and medical device companies on behalf of both lenders and potential buyers (domestic and foreign)
  • Analyzing medical literature and patient charts for healthcare clients seeking risk analysis under federal anti-kickback statute
  • Providing analysis of expert opinions under Daubert for a major managed-care company in the In re Managed Care Litigation in federal court
  • Analyzing coding and billing practices of physicians and providing critical analysis of expert witnesses on CPT (Current Procedural Terminology) coding
  • Investigating facts and developing analysis to defend a medical device company against multiple tort claims, including claims asserted under California’s Unfair Competition Law
  • Analyzing and identifying factual basis for defeating RICO claims asserted against healthcare clients


  • Farsi


Bar Admissions

  • California

Court Admissions

  • US District Court, Central District of California


  • University of Southern California, J.D.: Order of the Coif
  • University of Southern California, Marshall School of Business, M.B.A.: Beta Gamma Sigma
  • University of Washington Affiliated Hospitals, post-graduate training in Internal Medicine
  • University of California at San Diego, M.D.
  • University of California at Berkeley, B.A., Molecular and Cell Biology/Neurobiology: Phi Beta Kappa

Professional Activities


  • “Attributable Risk And Specific Causation,” Law360 (November 2008)