Teucrium L. is a widely distributed genus often used for the treatment of digestive disorders and respiratory problems. The aim of the present study was to determine the chemical composition of essential oils and elemental content of the plant species Teucrium polium, Teucrium hircanicum, Teucrium botrys, Teucrium chamaedrys, Teucrium flavum, Teucrium orientale, and Teucrium scordium of Moldovan origin, as well as to evaluate the antimicrobial activity of their extracts. The composition of essential oils was determined using gas chromatography–mass spectrometry (GC–MS), and neutron activation analysis (NAA) was used to assess the elemental composition of plants. Antimicrobial tests were performed in vitro on the Bacillus subtilis, Pseudomonas fluorescens, Xanthomonas campestris, Erwinia amylovora, Erwinia carotovora, and Candida utilis strains using the double-dilution method. GC–MS allowed the identification of 59 components of the analyzed essential oils, and showed that the analyzed species belong to four different chemotypes. Using NAA, 18 major and minor elements, the contents of which fell within the value ranges reported for other medicinal herbs of this genus, were identified. The hydroalcoholic extracts from Teucrium spp. exhibited in vitro antibacterial and antifungal activity at 0.03–0.06% and 0.015–0.03%, respectively. The extracts from Teucrium spp. exhibited high antibacterial and antifungal activity, enabling their application for medical purposes.