a few factors such as age , stress , and emotions may lead to impaired learning , memory loss , amnesia , and dementia or threats like schizophrenia and alzheimer s disease ( ad ) . iranian traditional medicine ( itm ) recommends some herbs and herbal preparations for the treatment or prevention of cns problems . in this study , scientific evidence related to the effectiveness of itm herbal medicine on memory , learning and ad is reviewed . the scientific evidence of plant efficacy was searched in electronic databases including pubmed , scopus , sid , science direct , and google scholar by keywords such as memory , alzheimer , amnesia , learning and scientific plant names from 1969 to 2014 . the findings of this study confirmed the effectiveness of certain itm medicinal plants on enhancing memory and learning or in the treatment / prevention of amnesia and ad . some itm plants like melissa officinalis , crocus sativus and nigella sativa showed improving effects on memory and the treatment of ad in clinical trials . in some cases , most of the studies on itm plants were designed in animal models and a few herbs were evaluated in clinical trials on ad . furthermore , there are insufficient or no investigations on certain herbal medicines used in itm to confirm their effectiveness on memory and learning . therefore , further experimental and clinical studies are necessary to evaluate the effectiveness of these plants on memory and ad as well as determining their active components .
background : a few factors such as age , stress , and emotions may lead to impaired learning , memory loss , amnesia , and dementia or threats like schizophrenia and alzheimer s disease ( ad ) . 
 iranian traditional medicine ( itm ) recommends some herbs and herbal preparations for the treatment or prevention of cns problems.methods:in this study , scientific evidence related to the effectiveness of itm herbal medicine on memory , learning and ad is reviewed . 
 the scientific evidence of plant efficacy was searched in electronic databases including pubmed , scopus , sid , science direct , and google scholar by keywords such as memory , alzheimer , amnesia , learning and scientific plant names from 1969 to 2014.results:the findings of this study confirmed the effectiveness of certain itm medicinal plants on enhancing memory and learning or in the treatment / prevention of amnesia and ad . some itm plants like melissa officinalis 
 , crocus sativus and nigella sativa showed improving effects on memory and the treatment of ad in clinical trials . in some cases , active principles responsible for the efficacy of these plants on memory were also determined.discussion:most of the studies on itm plants were designed in animal models and a few herbs were evaluated in clinical trials on ad . 
 furthermore , there are insufficient or no investigations on certain herbal medicines used in itm to confirm their effectiveness on memory and learning 
 . therefore , further experimental and clinical studies are necessary to evaluate the effectiveness of these plants on memory and ad as well as determining their active components .