Antibiotics are compounds that can stop the reproduction or kill microorganisms, but for some reason, microorganisms in time show resistance to antibiotics. Using efflux pumps, the antibiotic entered into the bacterial cell is pumped out; therefore, it cannot act against bacteria. This situation increases antibiotic resistance in bacteria. Thus, microorganisms will develop multiple drug resistance against not only the antibiotic used but also many other antibiotics and rapidly spread to the environment. For this reason, antibiotic resistance has become a major problem all over the world, and new antibiotics and efflux pump inhibitor studies, which can affect these microorganisms that are resistant to multiple drugs are continuing rapidly. In this study, the behavior of 7 Escherichia coli, 1 Acinetobacter baumannii, 1 Enterococcus faecium, and 1 Klebsiella pneumoniae strains having active efflux pumps and developed multidrug resistance, against both fungal extracts and the current efflux pump inhibitor verapamil were investigated. In this study, the effects of some extracts in combination with antibiotics on MDR bacteria were investigated. The research was conducted using FTIR analysis. The FTIR results provided information about the mode of action of the extracts. According to the results of the FTIR analysis; in the extract - antibiotic combinations in which the inhibiting activities were seen, changes were observed mainly in fatty acids, proteins, carboxyl groups of free amino acids, polysaccharides, RNA/DNA, and also changes in the fingerprint region. It is important to carry out further studies in terms of confirming and expanding the data obtained.