INTRODUCTION: With increased life expectancy, there is an increase in aging population and prevalence of dementia. Ghrelin is a key regulator of spatial memory and cognition. The gut microbiome may affect the circulating levels of unacylated ghrelin (UAG) and acylated ghrelin (AG). Thus, we explore the potential association of the gut microbiome, AG, and cognitive health in the aging dementia patient. METHODS: 40 dementia patients and 40 controls were recruited. Fecal Microbiome analysis using 16S rRNA sequencing was performed on 18 samples. A mixed-method approach was employed for robust interpretation. RESULTS: Dementia patients had an increased serum AG and AG/UAG ratio. With the increase in AG among dementia subjects, a significant decrease in species richness was observed. DISCUSSION: This pilot study indicates a complex interaction between AG, gut microbiome, and cognitive scores. Increased AG corresponds to both dementia and gut dysbiosis, intricately interconnecting the gut-brain axis. The circulating AG and associated gut microbiome might be a putative biomarker for dementia.