Abstract:Introduction and objective: The concepts of keyword and subject descriptor are usually exchanged, however it is wrong from a documentary standpoint. The objective of this report is to clarify concepts...Introduction and objective: The concepts of keyword and subject descriptor are usually exchanged, however it is wrong from a documentary standpoint. The objective of this report is to clarify concepts and guidance on their use. Method: Narrative review. The differences between natural language and controlled vocabulary as well as their implementation and impact on the retrieval of information was established. Results and conclusions: The distinction between the two concepts is clear and necessary to interrogate any source of information. Most of biomedical scientific journals contribute to this misuse. The difficulty for using the thesaurus by authors is clearly noticeable in the mistakes they made in the selection of keywords versus the assigned subject descriptors to the article in the end.Read More