Drug consumption in older people is usually high and many prescribed medications have unsuspected anticholinergic (ACH) (Table 1) properties. Drug induced ACH side-effects are particularly severe in aging brain and even more in demented patients. This review will focus on the association between ACH drug intake and the risk of developing central nervous system side-effects in elderly people. The threat of developing cognitive impairment, psychosis and delirium will be particularly analyzed.