There were five (20%) drop-outs in the Ginkgo bi- loba group and four (16%) drop-outs in the donepezil group. Considering the limited sample evaluated, Ginkgo biloba group shows a small dropout rate, which indicates that it has a good side effect profile. The drop- outs in the donepezil group were due to adverse events (diarrhea, nausea, vomiting and restlessness), the same observed in other studies [13]. On the contrary, the drop-outs in the Ginkgo biloba group were not imputable to adverse events, so that the Ginkgo biloba E.S. has demonstrated a confirmed good tolerability (Table 3).