Crude extracts from several medicinal plants were investigated for their antimicrobial activities against Colletotrichum spp. in grapevines Extracts of sweet wormwood, cockscomb flowers, asian plantain flowers, and peach tree resin showed in vitro antifungal activity on growth of Colletotrichum acutatum. To test inhibition effects of ripe rot development by C. acutatum and C. gloeosporioides, grapevine leaves were sprayed with each extract (500 fold diluted) from sweet wormwood and cockscomb flower and leaves, asian plantain flower and peach tree resin. The crude extracts of medicinal plants displayed remarkable in vivo antimicrobial activities with inhibition of lesion development by 22.5 to 67.5 % in ‘Blanc seedless’ and 2.12 to 53.2% in ‘Thompson seedless’ inoculated with agar block of C. acutatum and by 19.2 to 61.5% in 'Blanc seedless' and 19.6 to 78.3% in ‘Thompson seedless’ grapevines inoculated with spore suspension of C. acutatum compared with the untreated control. The crude extracts of medicinal plants showed remarkable inhibition of ripe rot by 26 to 64.8 % in ‘Blanc seedless’ and 25.5 to 76.5% in ‘Thompson seedless’ grapevine leaves inoculated with C. gloeosporioides agar block inoculation and by 23.1 to 61.5% in 'Blanc seedless' and 18.8 to 25% in ‘Thompson seedless’ grapevine leaves inoculated with C. gloeosporioides spore suspension compared with uninoculated control. These findings indicate that medicinal plant extracts could be used as possible candidates to control ripe rot disease environment friendly in grapevines.