A practical experiment was conducted for fourth-year students in the drug and toxicology laboratory under the supervision of Assistant Professor Mazen Hamid Odeh and Assistant Lecturer Sarah Najm Abd on the mechanism of evaluating various types of analgesic medications. An introductory theoretical lecture was given on the nature of pain, its types, how it occurs, the body’s response to different types of pain, pain-relieving medications, and their mechanism of action. Then a practical experiment was conducted in laboratory animals (rats), where pain was induced using an irritant substance, which is acetic acid at a concentration of 1%, injected into the peritoneum. The experiment showed some clear signs of pain in the animals, which are called writhing signs. Then, after that, the animals were injected with diclofenac sodium and… acetylsalicylic acid, and the results for the two substances were compared in terms of their analgesic effects in relieving pain in animals injected with the irritant. It is worth noting that this model of induced pain in mice is a model that is not specialized for a specific drug class, as many analgesic drugs can be tried in their various known drug classes.