Tropaeolum majus is a herbaceous plant that belongs to the Tropaeolaceae family. It is native to the Andes mountain ranges, where it is considered as an important herb in their traditional medicine. However, this plant has known, over time, a wide distribution all over the world, including north Africa. Indeed, Tropaeolum majus has shown in recent years a noteworthy flowering in northeast Algeria, where reigns a Mediterranean climate. The aim of this comparative study was to conduct a preliminary assessment of the phytochemical composition and antimicrobial activity of Tropaeolum majus that grows under the Mediterranean climatic conditions of Annaba city in northeast Algeria. Thus, a phytochemical screening of 20 metabolites families was performed on free-air dried and pulverized leaves, flowers, and fruits of this plant using standard qualitative analysis methods based on colour / precipitation reactions. Afterwards, methanolic leaves and flowers extracts, and fruits fixed oil were prepared and served for the functional groups analysis using Fourier Transform Infra Red spectroscopy (4000-400 cm -1 ), as well as the antimicrobial screening using the disc-diffusion method. Apart from narcotics and free anthracene derivatives; that are absent in the three organs, the phytochemical screening revealed the presence, in Tropaeolum majus, of the sought metabolites, mainly phenolic compounds, coumarins, sterols, triterpens, iridoids, and alkaloids. However, the nature and predominance of these metabolites differ between organs, with a unique presence of saponosides in fruits, and that of free quinones in flowers. Likewise, FTIR analysis revealed absence of infrared radiation absorption in the region between 2260-2220 cm -1 , which indicated absence of toxic cyanide groups; but showed distinct peak values, with a specific infrared radiation absorption in the region located between "1700-700 cm -1 ", revealing the presence of various functional groups in the three extracts, including aromatic, nitrogen, and sulfur compounds. Tropaeolum majus extracts were found to exert a good antimicrobial activity against tested Gram (+) and Gram (-) germs, especially against a troublesome food poisoning germ: Bacilluscereus, and the antibiotic-resistant genera: Pseudomonas, Acinetobacter, Staphylococcus, Enterococcus, and Klebsiella. These findings show that Annaba City Mediterranean climate factors improved Tropaeolum majus leaves, flowers, and to a second degree fruits nutritional and medicinal qualities enhancing their phytochemical composition as well as antimicrobial properties. Hence, this study suggests that this plant could be a potential source for different nutraceutical products that can be used as food additives or dietary supplements.