perioperative analgesia aims to minimize, or even eliminate pain during a surgical procedure. Currently this approach is rarely performed using a single analgesic drug and more commonly different types of analgesic drugs, such as opioids and non-steroidal anti-inflammatory drugs (NSAIDs), are combined. This approach is known as multimodal or polymodal analgesia and also includes other analgesic drugs and techniques such as alpha-2 adrenergic receptor agonists, ketamine, or loco-regional analgesic techniques. Another approach is the anticipation to perioperative pain by administering analgesic drugs before surgical injury occurs and thus preventing the animal suffering from pain. This approach is known as preemptive analgesia and may reduce pain not only intraoperatively but also postoperatively. Other relevant aspects include the expected pain intensity, which allows us to select the appropriate drugs or drug combinations. The duration of analgesic therapy should also conform to the expected duration of pain so as to provide the necessary coverage postoperatively. Fortunately, there are on the market analgesic formulations with an effect typically lasting 24 hours with some of them providing analgesia up to 4 days following a single drug administration. Despite these advances, a good postoperative analgesia can only be obtained with an appropriate pain assessment system that would allow changes to the analgesic regimen in order to limit or prevent pain effectively.