Over the past few years, animal welfare has taken more place in society and particularly in scientific research. It has become necessary to refine the experimental procedures as much as possible in infectiology as in our reference model, toxoplasmosis, in agreement with the 3Rs rule and the different ethical concerns existing since 1959. Thus, the establishment of a treatment using analgesics would provide relief in animals acutely infected with Toxoplasma gondii. However, the use of this analgesic should in no way alter the pathophysiology of the parasite and the immune response of the host, so as not to interfere with the initial scientific study. Currently, little is known about the use of paracetamol in an infectious model. In the present work, we studied the impact of paracetamol in the murine model of toxoplasmosis. To do this, zoonotic, telemetric, behavioral, histological and immune parameters were analyzed to better characterize the consequences of a treatment with paracetamol. Paracetamol administered by force-feeding (30 mg / kg / day) appears to be a good pharmacological tool in a mouse model of toxoplasmosis without modifying the major pathophysiology or the immune responses induced by T. gondii in both acute and chronic phases. These first results in mice validated our initial hypothesis that paracetamol appears to be a pharmacological tool for refining and improving animal welfare. Therefore, our project has highlighted the combination of specific markers to contribute to animal welfare in mice, with a view to transferring it to the target species, the sheep. In the long term, the use of paracetamol could be extended to other infectious models with other target animal species.