Paracetamol (acetaminophen) and ibuprofen are commonly used to relieve fever and pain in children. Their effects are similar, but differ in strength and mechanisms of action on the body. Acetaminophen, a para-aminophenol derivative, has antipyretic and analgesic properties. Despite the fact that paracetamol has been officially used as a drug for more than 75 years, its mechanism of biological action has not been sufficiently studied. In paediatric practice, paracetamol is more often used as an antipyretic, but in recent years, with the development of technology and emergence of new dosage forms on the market, it came into common use as an analgesic in many diseases, including oncological, rheumatological, etc. Ibuprofen is the most commonly used non-steroidal anti-inflammatory drug with pronounced analgesic and antipyretic properties. Ibuprofen, a non-selective inhibitor of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), affects the hypothalamic thermoregulatory center via inhibition of prostaglandin synthesis. In the paediatric population, the most common indications for the use of ibuprofen are fever, sore throat, ear pain, headache and toothache, post-traumatic and musculoskeletal pain, and inflammatory joint diseases. Paracetamol and ibuprofen are safe for use in paediatric practice, if dosing rules are observed, and are approved for use by the World Health Organization, FDA and other expert organizations. In addition, the emergence of new presentation forms of these drugs is most important in paediatrics.