Background Sauropus androgynus leaves is the substance which has the potency to prevent degenerative processes. Sauropus androgynus leaves has flavonoid as the main component. Flavonoid has antioxidant and anti neuro-inflammation that can be used to prevent Alzheimer dementia. Research purpose is knowing the effect of Sauropus androgynus leaves for the cognitive function and β-amyloid expression in the hippocampus of wistar rats. Methods Reseacrh was done by in vivo method, where male wistar rats (n=24) were distributed to six groups which consisting of four rats. Group 1: Normal control, group 2: positive control, group 3: standard treatment (B12 vitamin), group 4, 5 and 6 were give Sauropus androgynus leaves extract with the dose of 75 mg/kgBB, 150 mg/kgBB and 300 mg/kgBB, respectively for 28 days. Cognitive function was evaluated by t-maze test, where hippocampal β-amyloid expression was tested by immunohistochemistry. Results Time differences (day 0-28), alternation ratio distinction (day 0-28) and β-amiloid expression were: group 1 (1,84 second; 0,23 unit; 0,518%), group 2 (56,78 second; -0,42 unit; 40,036%), group 3 (34,46 second; -0,25 unit; 33,08%), group 4 (32,83 second; -0,09 unit; 28,88%), group 5 (-3,91 second; 0,42 unit; 14,728%), group 6 (24,25 second; 0,42 unit; 9,4%). Conclusion Sauropus androgynus leaves extract at the dose of 150 mg/kgBB and 300 mg/kgBB can maintain cognitive function by decreasing hippocampal β-amyloid formation.