This research was conducted to study the effect of the application of several extracts of medicinal plants on the incidence of mosaic disease caused by Cucumber Mosaic Virus infection on the chili (Capsicum annuum L.) plantation. A Randomized Block Design with eight treatments including control was used throughout the experiment. Treatments consisted of Azadiracta indica (A), Piper bitle (B), Cymbopogon citrates (C), Curcuma domestica (D), Averroa bilimbi (E), Datura stramonium (F), Annona Muricata (G) and control (H). Each treatment consist of three replications. The parameters observed were the incidence of mosaic attack due to CMV, disease severity, plant height, wet and dry weight and production (number of fruits and the weight of total fruits) each plant. Results showed that the application of medicinal plant extracts reduced the disease severity due to CMV. Extracts of Annona muricata and Datura stramonium were most effective in suppressing disease severity caused by the virus as they significantly different from control and from a number of treatment. The plants medicinal extracts were found to have increased the plant height and total weight of the plant, fruit amount and fruit weight. Extracts of Curcuma domestica, Piper bitle and Cymbopogon citrates were the third highest in fruit amount and weight and significantly different from the control.