Products Liability Law Reporter

A Missouri appellate court held that a trial court had not erred in excluding a plaintiff’s expert witness and in overruling his motion for new trial in a products liability case against Monsanto Co.

Stacey Moore sued Monsanto Co., alleging his long-term exposure to Monsanto’s glyphosate-containing products, including Roundup, led to his non-Hodgkin lymphoma (NHL). Before trial, the plaintiff disclosed oncologist A.S. as an expert witness who would testify regarding causation. The trial court sustained the defendant’s motion in limine to exclude A.S.’s testimony on the basis that he was unqualified. At trial, the court denied the plaintiff’s renewed request to call A.S. as an expert. The jury later returned a defense verdict and overruled the plaintiff’s motion for a new trial.

Affirming, the appellate court noted that the admission or exclusion of evidence lies within the trial court’s discretion. The plaintiff’s offer of proof here demonstrated that A.S. had ventured beyond his area of expertise, the court found, stating that the he was not credentialed in epidemiology, genetics, or biostatistics and was unable to identify on which particular studies he based his opinion. Moreover, the court stated that A.S. did not testify to having any experience with analyzing the types of epidemiological studies on which he intended to rely. The court also found that his use of a differential diagnosis to show causation was unreliable, noting that he had used his own conclusion that glyphosate caused NHL despite the fact that he was not qualified to give such a conclusion.

Consequently, the court held that the trial court had not abused its discretion.

Citation: Moore v. Monsanto Co., 2024 WL 4018871 (Mo. Ct. App. Sept. 3, 2024).