Sir: Keywords are essential tools for searching scientific articles in databases such as ISI and MEDLINE (PubMed). Keywords do not follow any structured search strategy; they are words of the free language, extracted randomly from the text.1 However, keywords are frequently unable to completely represent the subject of the article or may not be common among the authors. Descriptors were created to fill this gap. Descriptors are words of a controlled vocabulary used to organize, facilitate, and guide the user in the search for exact information from scientific articles of a specific database, sharing the same terms.2 These terms can be translated in a strict way, so that some descriptor databases can have controlled translations for these terms. A controlled vocabulary is a collection of organized terms that follow a special methodology. It is used to refine the search and to facilitate the access to medical information.3 The use of descriptors facilitates, improves, and expands the search. They can be used isolated or combined with other descriptors, refining the search. It is also possible to associate these terms with other types of information, such as year, author, and others.2 The Medical Subject Heading (MeSH) is the U.S. National Library of Medicine's controlled vocabulary used for indexing articles for MEDLINE/PubMed. It consists of sets of terms naming descriptors in a hierarchical structure that permits searching at various levels of specificity. The terms found in MeSH are updated yearly; therefore, every year, new terms are included or excluded as descriptors.2 MeSH is the most widely used database of descriptors.4 It is possible to obtain the same controlled vocabulary in English when entering a Spanish or a Portuguese term and vice versa. Some words used in the plastic surgery vocabulary (e.g., abdominoplasty) do not exist in the MeSH database. This occurs because it was not suggested by researchers to be included. The important fact for our specialty is that the adequate use of descriptors could increase the citation of the published articles. This will consequently increase the spread of knowledge, facilitate and refine literature search, and unify the scientific language.5 Each journal has its own criteria regarding the use of keywords, and it is up to the editorial boards to decide whether MeSH descriptors should be used or not. The level of the editorial board and reviewers, type and quality of the selected articles, the language used, and indexed database are important factors but not the only factors responsible for the impact factor of the journal. The use of the MeSH database could increase the number of articles cited, increasing the impact factor of the journal. Although MeSH is more used for basic science research, an effort should be made by plastic surgeons and the national societies to feed this database with plastic surgery terms to make this fabulous instrument work for our specialty. Ana B. Tedesco Fabio Xerfan Nahas, M.D., Ph.D. Lydia M. Ferreira, M.D. Federal University of São Paulo São Paulo, Brazil