Infectious diseases caused by bacteria, viruses, parasites and fungi, and their interaction with hosts and the environment are a global public health threat. In antimicrobial drug discovery from natural products, this potentiation of the antibiotic activity has been described as in the case of clavulanic acid and recently ellagic and tannic acids against multidrug-resistant microorganisms (MDR) strains of Acinetobacter baumannii. Biofilms are microbial communities attached on a surface, which are embedded in a matrix that provides a reservoir for microbial cells and confers a protection against biocides and drugs contributing to drug resistance development. Several foodborne diseases are caused by bacterial toxins that negatively affect the quality of foods, therefore the search for inhibitors is required to ensure the safety of the foods. Synergy research of the mixture of bioactive constituents can improve the application of phytopharmaceuticals in antimicrobial drug discovery programs. EOs are sensitive materials which can easily suffer degradation under the action of oxygen, light and moderate temperatures.