Traditional medicine uses many plants in the preparation of medicinal recipes for the treatment of human pathologies. These plants are thus indispensable to the existence of all living beings, because they provide all the necessary elements for their survival. Man, to ensure a daily well-being, uses plants in various fields including traditional medicine. The purpose of this work is to determine some toxicological parameters of the decocté of the leaves of Vernonia colorata (Asteraceae) and Crescentia cujete (Bignoniaceae) in order to control the dosage and prevent poisoning in the therapeutic use of these plants. The acute toxicity of aqueous decoction of these species was assessed following a process of orally administering raw decoctions to mice at increasing doses ranging from 6000 to 7500 mg/kg body weight (bw). Phytomedicines were used orally at different doses. The results obtained the solubility limit dose corresponding to the maximum tolerated dose or DTM of 6000 mg/kg and 7500 mg/kg respectively for Vernonia colorata and Crescentia cujete. This toxicological endpoint (maximum tolerated dose) is far greater than 21.04 and 100.33 mg/kg body weight of the daily doses recommended by traditional healers. Therefore, the doses prescribed by traditional healers are not toxic. The use of these plants under traditional conditions of preparation and oral administration against diabetes may be scientifically justified.