Lippia gracilis essential oil (LGEO) was evaluated for its molluscicidal activity against Biomphalaria glabrata and toxicity to brine shrimps (Artemia salina). L. gracilis was collected from the city Tomar do Gerú-Sergipe, Brazil. The LGEO were characterized by gas chromatography-mass spectrometry (GC/MS). The values of LC 10 , LC 50 and LC 90 were respectively 36.9, 62.2 and 82.8 ppm for B. glabrata and 19.6, 23.6 and 26.1 ppm for A. salina. GC/MS analysis showed a total volatile content of 98.6% in the LGEO. The major components were identified as thymol (24.0%), p-cymene (15.9%), methyl-thymol (11.7%), γ γ γ γ-terpinene (10.9%) and β β β β-caryophyllene (7.8%).