Spearmint or mint, Mentha spicata a perennial plant of the family Lamiaceae (or Labiaceae, Labiatae), of the genus Mentha, cultivated as an aromatic plant, is a species widely used in traditional medicine for its biological properties attributed mainly to polyphenols. In the context of the valorization of medicinal and aromatic plants of Morocco, during this study, we focused on the phenolic compounds identification, antioxidant activity (in vitro) and acute oral toxicity in wistar rat of the Moroccan Mentha spicata plant collected in the Casablanca region- Settat (benslimane province). The results of the antioxidant activity assay showed that the polyphenol assay shows that the methanolic extract is better than the aqueous extract with respectively 2.14 ± 0.34 GAE/g DW and 0.682 ± 0.07 GAE/g DW. Even for the flavonoids with respectively 2.81 ± 0.38 QE/g DW and 0.79 ± 0.02 QE/g DW, but for tannins the results show that the aqueous extract is better than the methanolic extract with 156.96 ± 69.52 CE/g DW and 95.7 ± 86.26 CE /g DW respectively. It is also concluded that the methanolic extract has a higher activity antioxidant than the aqueous extract with EC50 values of 0.173 ± 0.013 mg/ml and 0.191 ± 0.07 mg/ml, respectively. Regarding the acute oral toxicity in wistar rat, the values revealed that there was a similar range of Lethal dose 50 (LD50) dose values for the two extracts of the plant Mentha spicata, from 5000 to 7500 mg/kg of the body weight of the rats. The determination of the (LD50) of ethanol extracts of Plant of Mentha spicata, showed that from the dose 5000 mg/kg, hypo activity was observed in rats, while for the aqueous extract it is from 10,000 mg/kg that hypo activity appeared. General signs of toxicity due to large doses of this plants extract, which is significant compared to the other parts.