Antibacterial activity is the most widely studied aspect of plant extracts. Antibiotics extensively produced and consumed in large quantities, have proved to be problematic due to various types of adverse effects. The development of bacterial resistance to currently available antibiotics has necessitated the search for new antibacterial agents. One of the alternative strategies for fighting antibiotic- resistant bacteria is the use of natural antimicrobial substances such as plant extracts. We tested the antimicrobial activity of nine extracts from different plants against pathogenic bacteria isolated from the faeces of red deer (Cervus elaphus). Selected bacteria commonly contaminated the natural environment and constitute a source of infection in other animals and humans. Extracts obtained from the following plants were tested: Hypericum perforatum L., Chamomilla recutita L., Achillea millefolium L., Salvia officinalis L., Thymus vulgaris L., Pinus sylvestris L., Mentha x piperita L., Valeriana officinalis L. and Foeniculum vulgare Mill. The highest degree of antibacterial properties was observed for Mentha x piperita L., narrower spectrum of activity possessed Hypericum perforatum L. Extracts of Achillea millefolium L. had the lowest spectrum of antibacterial activity. Our study confirms that many plant extracts shows in vitro antibacterial activity.