Aims: This study was aimed at analyzing the phytochemical constituents, evaluated the in vitro filaricidal activities of the ethanolic extracts of G. arborea on Onchocerca ochengi and carried out the acute and sub-acute toxicity on rats. Place and Duration of Study: The work took place at the Laboratory of Applied Zoology of the Faculty of Science of the University of Ngaoundere between June 2020 and April 2021. Methodology: Quantitative determination of total phenols, total flavonoids and tannins were performed by using standard titration curve of gallic acid and rutin. The adult male worms of O. ochengi were incubated in Roosevelt Park Memorial Institute (RPMI-1640) medium supplemented with antibiotics containing different concentrations of the plant extracts and ivermectin (positive control). The mortality of worms was evaluated using the MTT/formazan colourimetry test after 24 h and 48 h. Acute and sub-acute toxicity tests of G. arborea were evaluated on rats according to OECD 425 and 407 respectively. Results: The quantitative phyto-constituents screening revealed that total phenols (873.33 ± 3.33 mg GAE/g) were the most quantified compound followed by tannins (229.33 ± 0.33 mg GAE/g) and total flavonoids (116 ± 1.01 mg RE/g) in the roots of the plant. 0.22 ± 0.02 mg/mL, 0.17 ± 0.00 mg/mL, 0.16 ± 0.01 and 0.11 ± 0.01 mg/mL were respectively the LC50 of hydroethanolic extracts of the leaves, barks, roots and ivermectin at 48 h. The acute and sub-acute toxicity test showed no toxicity in rats. Conclusion: Looking at the result, the extracts of this plant may be used in novel drug discovery to fight against onchocerciasis.