Acetylsalicylic acid (ASA) is one of the most commonly used drugs in the world. It derives from the extract of white willow bark, whose therapeutic potential was known in Egypt since 1534 BC. ASA's pharmacological effects are historically considered secondary to its anti-inflammatory, platelet-inhibiting properties; however, human studies demonstrating a pro-inflammatory effect of ASA exist. It is likely that we are aware of only part of ASA's mechanisms of action; moreover, the clinical effect is largely dependent on dosages. During the past few decades, evidence of the anti-infective properties of ASA has emerged. The study performed a review of such research in order to provide a comprehensive overview of ASA and viral, bacterial, fungal and parasitic infections, as well as ASA's antibiofilm properties.