Pseudomonas aeruginosa is a gram-negative pathogen of great concern in immune-compromised individuals and the major cause of mortality in cystic fibrosis patients. Its pathogenicity lies in the production of myriad of virulence factors such as phenazines (pyocyanin), exoenzymes (elastase B), siderophores, exopolysaccharides and surfactants (rhamnolipids), among others. In addition, P. aeruginosa forms aggregated communities of cells encased in an extracellular matrix known as biofilms making it resistant to most of the available antibiotic agents. Following the discovery of quorum sensing (QS) system, involved in the regulation of virulence factors, resistance, and biofilm formation in P. aeruginosa, anti-virulence therapy has been adopted as a novel approach to combat the multi-drug resistance bacteria. In view of this, there has been extensive search in natural products for chemotherapeutic compounds that can override the virulence factors and their regulation by the QS communication system without affecting bacterial growth. Since plants are known repositories of secondary metabolites with chemical defense systems against environmental microbes, in this study, extract from Mulinum crasiifolium Phil. of Apiaceae family, was investigated for anti-virulence factors and anti-biofilm activities against P. aeruginosa. To perform virulence factors quantification assays, P. aeruginosa was grown in absence or presence of M. crasiifolium extract (McE) at different concentrations. The obtained results showed that McE hinder significantly pyocyanin pigment production without disturbing bacterial growth. Moreover, this anti-pyocyanin activity was found to be dose-dependent. The results demonstrated also that McE decreased elastase and rhamnolipid production. All of these effects seem to be associated to the inhibition of QS molecules production and the alteration of membrane fluidity. As a future work, we intend to evaluate the effects of the McE on in vivo models and further fractionate the McE and identify the bioactive compounds and their mechanisms of action.