This paper examines the epistemological warrant for a toxicological phenomenon known as chemical hormesis. First, it argues that conceptual confusion contributes significantly to current disagreements about the status of chemical hormesis as a biological hypothesis. Second, it analyzes seven distinct concepts of chemical hormesis, arguing that none are completely satisfactory. Finally, it suggests three ramifications of this analysis for ongoing debates about the epistemological status of chemical hormesis. This serves as a case study supporting the value of philosophical methodologies such as conceptual clarification for addressing contemporary scientific disputes, including policy-related scientific disputes that may be heavily influencedby social and political factors.