The immune system is part of the homeostasis system. Our research is focused on ways to maintain health, with an emphasis on the role of macrophages. We have hypothesized that tissue macrophages form a systemic network which we believe contributes to the homeostasis system, and have named it the 'macrophage network.' This network creates a dynamic equilibrium situation where macrophages control homeostasis. Our research is based on this macrophage network theory as we believe that the innate immune system provides the foundation for the homeostasis system. As part of our research, we have demonstrated that macrophage activation can provide protection and therapeutic effects for various diseases. Therefore, we have also focused on lipopolysaccharide (LPS). We proved that the LPS of Pantoea agglomerans (which we have named IP-PA1) was useful in preventing various health disorders and in restoring health when administered via the oral or transdermal route. We also developed a 'fermented flour extract', which consists largely of IP-PA1. For LPS to become a valuable commodity, it is very important to provide assurance about safety (when administered orally or transdermally) to build confidence. For this reason, we tested fermented flour extract (in which the major component was IP-PA1) to confirm that it was safe. The results of these safety trials confirmed that oral and transdermal administration of fermented flour extract was very safe. Thus, we believe that fermented flour extract is a new substance that will have applications in health food, cosmetics, animal feeds, fisheries feeds and drugs industries.