As the aggregation of Αβ peptide has been considered as one of the pathogenesis of Alzheimer's disease, development of the potent inhibitor has been required for its complete recovery. We have identified rosmarinic acid with a major Αβ aggregation inhibitor of summer savory, one of the member of Lamiaceae. Therefore, we designed several rosmarinic acid derivatives for anti-Αβ aggregation drug candidates. Anti-Αβ aggregation activity was evaluated by our developed method “micro littlers scale high-throughput screening (MSHTS) system”. The results showed the presence of the phenol hydroxyl group and hydrophobic alkoxy group is very important for the activity. The docking study between Αβ42 and synthesized compounds and their ThT assays are ongoing. The details of SAR studies of rosmarinic acid derivatives with Αβ42 will be presented.