Simply defined, gut dysbiosis refers to a condition in which the ratio of beneficial and harmful bacteria present in the small or large intestine is disrupted and the ratio of harmful bacteria increases. Because an increase in pathogenic bacteria leads to damage to intestinal mucosal cells, it is important to provide functional medical treatment that not only removes harmful bacteria and supplies beneficial bacteria, but also helps restore damaged intestinal mucosal cells when treating patients with intestinal bacterial imbalance. In addition, the intestinal environment where intestinal bacterial imbalance can occur must be corrected, and further education on lifestyle habits and environments where gut dysbiosis can occur must be provided. In these ways, various approaches are needed to treat patients with gut dysbiosis, and in this review, the author will describe functional medical approaches using the 5R (remove, replace, reinoculate, repair and rebalance) program in these patients.