The only standard therapy for AD are acetylcholine-esterase inhibitors (AchEI; donepezil, galantamine, rivastigmine). AchEI exhibit a temporary stabilizing mild effect on the progression of AD. Conversion rates from "mild cognitive impairment" to AD do not seem to be beneficially influenced by AchEI. A high percentage of premature study withdrawals owing to adverse events has been observed in AchEI studies published to date. The questionable benefit may further be outweighed by high costs of the AchEI.