Figure 1. Participation of the intestinal microflora in inflammation and the development of BPH. Disturbances in the intestinal microflora (dysbiosis) can be caused by many factors, among them bad diet that is poor in plant fiber and starch sources. Additionally, the state of intestinal eubiosis may be disturbed by taking antibiotics and other medications, e.g. in the treatment of diabetes or depressive disorders. The specific intestinal microflora—‘obese microbiota’—is found in overweight people and it additionally affects metabolic processes in these people. A different gut microbiome is also observed in people with inflammatory bowel diseases (IBS, IBD). Proper intestinal microflora and its metabolites produced in the fermentation process, including short-chain fatty acids (SCFAs) contribute to the maintenance of intestinal epithelial cell homeostasis, and are a source of energy for colonocytes (mainly butyric acid). Intestinal dysbiosis and changes in SCFAs levels are factors that reduce the protective mucus layer, weaken tight junctions between intestinal epithelial cells, and cause leakage of the intestinal barrier. When the intestinal barrier is disturbed, pathogenic factors, inflammatory factors (immune cells and cytokines) and bacterial metabolites produced in varying amounts, e.g. SCFAs and toxic metabolites enter the bloodstream and migrate to distant tissues and organs. Inflammatory and microbiological factors, along with the peripheral circulation, may also reach the prostate gland, where they cause local inflammation. The inflammatory process in the prostate can activate signaling pathways involving growth factors, thus resulting in the prostate proliferation.