Urgency: Effect of Centella asiatica (CA) and aerobic exercise on Amyloid beta-42 (Aβ42) and phosphorylated tau (p-tau) as biomarkers of dementia is not yet known. Objectives: This study aimed to analyze the effect of CA, aerobic exercise, and their combination on Aβ42 and p-tau in older women with dementia. Design: It was a 24-week randomized, double-blind controlled trial. Partisipant: Subjects were divided into four groups: the Centella asiatica group (CA, 1x500 mg/day, n = 16), the aerobic exercise group (AE, 3x60 minutes/week, n = 16), the CA-AE combination group (1x500 mg/day and exercise, n = 15), and the placebo group (n = 15). Instruments: The dementia screening test used the Mini Mental State Examination (Intraclass correlation coefficients : ranging from 0.60 to 0.93, sensitivity of 88.3%) and Clinical Dementia Rating questionnaires (sensitivity 93.6% and specificity 100%). The Wilcoxon, Kruskal-Wallis, and Mann-Whitney tests were used to analyze the data. Results: Plasma amyloid beta-42 showed an increase in all groups: CA (p<0.001), AE (p=0.001), CA-AE combination (p<0.001), and placebo (p<0.001). Meanwhile, plasma p-tau also decreased in CA (p<0.001), AE (p<0.001), and CA-AE combination (p=0.001). The Mann-Whitney test showed that Centella asiatica caused the highest increase in Aβ42 (∆=233.5; p<0.001). Conclusion: This study indicate that Centella asiatica, aerobic exercise, and the CA-AE combination were effective in improving plasma Aβ42 and decreasing p-tau in older women with dementia. Contributions: This study can be an alternative therapy for the prevention and treatment of cognitive decline. Research with a larger sample size is recommended.