Salicylate plays an important role as a non-steroid, anti-inflammatory drug. In poultry, those used most commonly are sodium salicylate (SS) and acetylsalicylic acid (ASA), due to their immunomodulatory, analgesic, antipyretic, and anti-inflammatory activities. Other effects have been reported such as minimising the effects of heat stress, allostatic load, ascites, leg disorders, reducing respiratory and digestive disorders, as well as enhancing growth performance, feed utilisation, nutrient digestion and absorption, egg production and the quality of meat and eggs. Furthermore, ASA plays a key role in lowering cholesterol and triglycerides in blood, meat and eggs, and improvements in immune functions and antioxidant enzymes have been noted in birds. This paper reviews the different characteristics and beneficial applications of ASA in poultry nutrition for improving immunity, production, and safeguarding health, especially under heat stress conditions.