tive approach, although more time consuming, than initially limiting searches to liver information because information not about liver toxicity per se, but possibly related to liver toxicity, could be identified.

To prepare the chaparral monograph, the databases indicated below were searched using the terms [chaparral] OR [Larrea tridentata] (in any field). In the AGRICOLA database, it was necessary to limit the search to exclude other meanings of the word “chaparral.” These searches were conducted in April 2002 and yielded approximately 125 citations (excluding duplicate citations brought up by the various databases). The databases were independently searched for the entire genus Larrea, and articles pertaining to the North American plant were investigated to confirm that all articles that actually reported on L. tridentata were considered. Citations for many references that predate the electronic databases were collected from among the reference sections of the literature reviewed. Because the number of published articles on this topic are limited, an effort was made to collect abstracts representing research in this area. In August 2002, the databases were searched again for more recent articles and a few citations were added. A literature search on NDGA was also conducted in April 2002 and yielded approximately 325 citations (excluding duplicate citations brought up by the various databases). As NDGA is commonly used as a reagent, the search parameters were limited as follows: [nordihydroguaiaretic acid] OR [NDGA] (in title field) for most databases; [nordihydroguaiaretic acid] OR [NDGA] (in any field) for TOXLINE and AGRICOLA.

Electronic searches were conducted using the following databases: PubMed (1966–2002, TOXLINE Core inclusive), TOXLINE (TOXLINE Core and TOXLINE Special), EMBASE (1980–2002), and AGRICOLA (1979–2002). It should be noted that EMBASE contains a considerable amount of foreign literature and AGRICOLA contains a considerable amount of the veterinary literature. WorldCat, EMB/Cochrane Reviews, IBIDS, BEAST, and Dissertation Abstracts were used to a limited extent. NAPRALERT was used for natural products. Patents were accessed using the website of the U.S. Patent and Trademark Office. Information on the SN/AEMS and regulatory actions taken by FDA were obtained from the FDA website. Information on regulatory actions by the Federal Trade Commission (FTC) was obtained from the FTC website. It is highly recommended that Chemical Abstracts also be used, although this database was not used for the prototype monographs due to the limitations of time and resources. In the database search, no restriction was placed on language or type of publication. However, the ability to interpret non-English-language publications was limited. The foreign language literature was included when it was deemed important in order to be complete. The majority of the