Is fentanyl an opiate? That’s the question the prosecutor asked a witness in State v Gibbs. The trial court overruled the defendant’s objection, and the witness was permitted to testify that fentanyl was both an opioid and an opiate. In an unpublished opinion (“Gibbs I”), the Court of Appeals ruled this was error, reversing a conviction for trafficking by possession. Our Supreme Court then reversed the Court of Appeals. In a concise, per curiam opinion, our Supreme Court declared that whether fentanyl is an opiate is a question of law, and it remanded for reconsideration. In a subsequent unpublished opinion (“Gibbs II”), the Court of Appeals determined that fentanyl is an opiate as a matter of law. Reasoning that there was no need for an expert witness to testify on the issue, the Court of Appeals concluded that there was no error in the defendant’s conviction for trafficking. Of course, whether such testimony is necessary does not resolve whether this particular evidence was admissible. Gibbs is an evidence case, but the rule it illustrates is elusive. This post examines Gibbs to ascertain whether the prosecutor asked a permissible question.