Introduction: the categorization of a bacteria as gram-negative responds to the staining and coloring it takes during the biochemical identification process using Gram staining. There have been multiple antecedents in relation to the study of bacteria, especially gram-negative ones. Objective: describe the challenges and advances in the study of gram-negative bacteriaMethod: in relation to the central theme of this research, a bibliographic review was developed. Search terms and their English equivalents were used. They were applied in search engines such as Google Scholar and databases such as Scielo Regional, PubMed and SCOPUS. We worked with 21 investigations to write this work. Development: Gram-negative bacteria share similar characteristics in terms of their structure in relation to Gram-positive bacteria. However, its main difference lies in the constitution of the wall. Research in the health sciences, especially in the area of microbiology, focuses mostly on the diagnosis of causal agents and the improvement of procedures for their confirmation. At the same time, they provide invaluable information on the basic characteristics of these agents that allow their identification and those that have changed over time. Every scientific advance finds relevant information, as well as new challenges for researchers. These challenges lay the foundations for new questions and unmask new horizons in search of new information on the topic investigated. Conclusions: in relation to advances, they have focused on determining the resistance capacities of bacteria, in coordination with their behavior in the environment and how these data could influence therapeutic alternatives. For their part, the challenges contribute to the improvement of the processes, especially from a technological point of view, to guarantee greater focus on the research carried out