Recently, The American Journal of Clinical Nutrition (AJCN) began reviewing articles about dietary supplements. The purpose of this commentary is to provide guidelines to authors and reviewers for articles on one category of supplement ingredients, botanicals. The botanicals in the studies published by the AJCN tend to fall into 1 of 2 groups: 1) plants as foods containing nonessential bioactive constituents that may provide health benefits beyond basic nutrition, and 2) plants as herbs, specifically those used as phytomedicines. Research in these areas is relevant to clinical nutrition, but both topics represent relatively new territory to many AJCN reviewers, readers, and contributors. Although studies of botanicals are unique in many respects, the research should be evaluated with the same basic criteria applied to other types of investigations. For example, a study cannot be evaluated or replicated unless the test materials are properly identified and characterized. Investigators must provide an accurate and complete description of the botanical test material regardless of whether it is a finished product, commercial ingredient, extract, or single chemical constituent. For herbal preparations, investigators are advised to follow the criteria used by researchers in the field of pharmacognosy. Finally, the quality of research related to botanical dietary supplements would be improved and cross-study comparisons facilitated if standard reference materials and certified methods of analysis were more broadly available.