The present study reports on the investigation of phenolic compounds and the determination of the biological activities, toxicity and analgesic effect Ceratonia siliqua, phenolic content was spectrophotometrically quantified with the microplate method, while the bioactivities of methanolic and aqueous extracts were assessed by determining of antioxidant activity. The methanolic extract showed high contents of total flavonoids and exhibited the highest in vitro antioxidant potential (DPPH, ABTS, Superoxide, FRAP, CUPRAC, and phenanthrolin). In the acute toxicity, no death was reported in a dose of 1000, and 1500mg /Kg BW, however the dose of 2000mg/kg BW showed many signs of toxicit y, so the DL50 is higher than 2000mg/Kg BW. In analgesic in vivo assay, the methanolic extract showed a very important capacity to reduce pain, whether central or peripheral, with a certain dose-dependent relationship. For the three tests (hot plate, tail flick and acetic acid assay), the effective dose was 500mg/kg and the effective duration was 30min to 1 hour. This study demonstrate interesting in vitro and in vivo effects of carob leaves extracts and suggests that could be used as an alternative to chemical compounds. According to the extracts concentration and nature, it is very interesting to use like a source of natural antioxidants and analgesic compounds that might be more widely used in pharmaceutical industries.