With the intention of selecting plants for use as a fungicide, a study was conducted on the invitro activity of 10 medicinal plants in the Kisangani area. The activity of 3 types of extracts (concentrated crude, ethanolic and ethereal) was tested on 3 phytopathogenic strains (Alternaria alternata, Alternaria solani and Fusarium sp.). The method of inhibition of mycelial growth on solid medium (PDA) in Petri dishes was used to study the activity of extracts of medicinal plants towards strains. 9 plants showed satisfactory activity for at least one type of extract on at least one of the fungal strains. However, the statistical evaluation concluded a lack of significant difference between the different extracts, and highly significant differences between different plants. Alchornea cordifolia is the only plant that has shown no efficacy on all fungal strains tested.