In the rational human diet, the important role of fruits and vegetables, which are a source of bioactive phytochemicals, is emphasized. Among fruits particular attention, due to a number of documented health-promoting properties, is focused on cranberry. This fruit is characterized by the high content of antioxidant phenolic compounds, which may support the natural antioxidant defense system of the body in the prevention of damage caused by oxidative stress induced by reactive oxygen species (ROS). Therefore, cranberry is suggested for the prevention of civilization diseases such as atherosclerosis, hypertension and cancer, whose etiology is associated directly with oxidative stress. The health-promoting potential of cranberry is also associated with its antibacterial activity resulting from the presence of proanthocyanidins (PAC) type A with documented anti-adherence properties. The best-established medical applications of cranberry fruits are prevention and treatment of bacterial infections of the urinary tract (UTI), infections of gastric mucosa, and infections of the oral cavity. Due to the widespread use of cranberry and pharmaceutical preparations containing PACs in treating UTI, it is very important to evaluate the absorption, bioavailability and metabolism of these compounds in the human body.