The oral cavity is the first part of the digestive and respiratory systems; it fulfills important vital functions. Its normal function is dependent on many factors, both internal and external. The oral mucosa is constantly exposed to the influence of external factors. In addition, various foreign bodies are more often placed in the mouth, for both therapeutic treatment and decoration. For example: oral piercing, braces, dental implants, amalgam fillings. All of these factors can adversely affect the function of the mucosa as well as the whole organism. This paper is a review of recent literature and an analysis of the impact of selected foreign bodies on the oral cavity and the whole body, with particular attention paid to the risks associated with piercing. Studies clearly show that the presence of foreign bodies in the mouth contributes to the formation of many pathological conditions and diseases. They can be just local complications, but in some cases also general. Literature reports indicate that the presence of foreign bodies in the mouth can also lead to complications that have serious consequences to overall health. The presence of foreign bodies, particularly in the oral cavity can adversely affect its functioning and health of the entire system.