The prevalence of antibacterial resistance has brought about a growing surge to develop novel approaches to control infectious diseases. Targeting Quorum-sensing (QS) - controlled virulence factors in bacteria has indicated a promising strategy for antipathogenic drugs. Extracts of Philippine Ilongot-Egongot ethnobotanicals Stachytarpeta jamaicensis, Adenanthera intermedia, Mikania micrantha, Hyptis suaveolens, Premna odorata, Cymbopogan winterianus, Phyllanthus urinaria, Dillenia philippinensis, Hydrocotyle vulgaris, Senna alata, Urena lobata, Ceiba pentandra, Ficus sp., Eleusine indica, Diplazium esculentum and Talahib (no known scientific name) were screened using microtiter plate biofilm formation assay for their QS inhibition activity against biofilm formation in Pseudomonas aeruginosa clinical isolate and Pseudomonas aeruginosa PNCM 1335. Extracts of M. micrantha, H. suaveolens flowers, H. vulgaris, A. intermedia, E. indica leaves, D. esculentum and Talahib have inhibitory effect on P. aeruginosa clinical isolate biofilm formation. Decrease in biofilm formation was shown in extracts of S. jamaicensis., M. micrantha, H. suaveolens, H. vulgaris, U. lobata, C. pentandra, A. intermedia, E. indica, D. esculentum and Talahib. against P. aeruginosa PNCM 1335.  RNA extracts of M. micrantha, Talahib and A. intermedia exhibited downregulation of lasR in both test bacteria using qRT-PCR analysis through absolute quantification. The prospects of these ethnobotanicals to inhibit bacterial virulence avoiding antibiotic resistance is presented in this paper.