Betty Ann Marsee’s husband, Sean, died from oral cancer. Marsee (plaintiff) brought a products-liability suit against United States Tobacco Company (USTC) (defendant), the manufacturer of a snuff product. Marsee alleged that Sean’s use of USTC’s snuff had caused his cancer. At trial, Marsee called Dr. Kent Westbrook as an expert witness. Westbrook testified that, in his opinion, using snuff could cause oral cancer. Westbrook also testified that, based on his review of Sean’s case, Sean’s cancer was caused by USTC’s snuff. On redirect examination, Westbrook testified that he had spoken with other doctors about snuff’s tendency to cause cancer. At this point, USTC objected on hearsay grounds. The district court sustained the objection and excluded any details of conversations that Westbrook had with other doctors about other patients. The jury found in favor of USTC. Marsee appealed, arguing that the district court erred by excluding Westbrook’s additional testimony.