Chikungunya virus (CHIKV) is an alphavirus that is transmitted to humans mainly by the Aedes aegypti or albopictus mosquito. Ever since the outbreak on Reunion Islands in 2005–2006, CHIKV is considered to be an emerging virus. In particular arthralgia or arthritis, affecting multiple joints, is very pronounced during the clinical course, and may last for as long as 2 years. Currently, no vaccine nor a selective antiviral drug is available for the prevention or treatment of this debilitating viral infection. Chloroquine is active in cell culture and may alleviate the symptoms of arthritis by acting as an anti-inflammatory agent, although this latter is still under investigation. In 2008, the CRVOI (Centre de Recherche et de Veille sur les maladies émergentes dans l’Océan Indien) has funded a research program that brings together four areas of expertise: the use of plants as natural source for the treatment of disease (ethnopharmacology), the identification and classification of plant species biodiversity, the purification and identification of unique molecules/secondary metabolites of natural origin, and the identification and characterisation of selective inhibitors of virus replication. Three teams, located on Reunion Islands, Mauritius and Madagascar, together with the ICSN, have build a unique sample library consisting out of more than 1500 crude plant extracts that have been evaluated for selective antiviral activity against CHIKV in Leuven and Marseille. Currently, a bio-assay-guided purification of pure substances is in progress, at present yielding the first results. Concomitantly, enzymatic assays are being developed in Marseille to evaluate and possibly characterize in detail the selective inhibitory effect of these compounds.