Gastroenterology and Hepatology Researchdation, and the possible putative prophylaxes to optimize cognitive decline in older adults with pre-diabetes symptom. Because of the diversities of placental extract and Aloe vera as biogenic stimulants, present review introduced the briefly selected authors' intentions in each topical subject. Specially, the influence of gut microbiota to host is astonishing and highlighting that the consequence of our behaviours affect not only the environment without, but also that within us. Based on geriatric and neurological viewpoint, present review highlights current therapeutic strategies of placenta extract and Aloe vera as the so-called "biogenic stimulants", aimed at producing a biological rejuvenator in placental extract and improving cognitive function via modifying the brain's insulin sensitivity in Aloe vera.