The medicine is either a substance or a combination of several substances used to diagnose, prevent, improve or cure a disease. The use of drugs provides many benefits, but it also involves risks because, following drug-body interaction, adverse effects or reactions occur. These undesirable reactions are favored by polymedication, long-term treatment and particular physiological states (pregnancy, breastfeeding, elderly) or pathological conditions (kidney failure). In daily practice, Paracetamol is a commonly used medicine, covering almost all specialties and age groups. It is part of non-opioid analgesics and antipyretics, often used to treat pains with different localizations and intensities. The purpose of this paper is to investigate the effects of experimental intoxication with Paracetamol, highlighting the beneficial effect of the Silybum marianum vegetal extract on the haematological index in NMRI Albino mice. We used paracetamol in the form of injection, known as perfgalgan (Bristol-Myers Squibb), at the dose of 400 mg/kg/body of substance, and the plant extract from Silibum marianum was given by oral gavage after Paracetamol intoxication. In order to accomplish the purpose of this paper, the number of hematiocytes, leucocytes and the amount of hemoglobin was determined in the four experimental variants: the control group, the group in which the mice were experimentally intoxicated with Paracetamol, the group in which, after the experimental intoxication with Paracetamol, the mice were treated with vegetable extracts of Silibum marianum , and the group in which the mice were treated only with Silibum marianum vegetal extract.