Acetaminophen, aspirin and caffeine used in combination are an effective method of treating acute headaches and migraines. The combination of these substances is considered superior to acetaminophen on its own when treating headaches. There are other benefits due to the individual components of the tablets. Acetaminophen (also known as paracetamol) is the most common analgesic and antipyretic around the world, it is an effective treatment for acute primary headaches on its own and can be combined with tramadol to treat cluster headaches. It has a very low risk of causing allergic reactions and so can be used by those with bronchial asthma. Aspirin is a first-line therapy to treat moderate to severe primary headaches as well as reducing pain, fever and inflammation. However, it is not taken by children under twelve due to the risk of Reye syndrome. Caffeine is considered an effective treatment for various types of headaches including post-dural puncture headaches and hypnic headaches. It also provides an increase in high energy exercise tolerance and reduces fatigue. These drugs combined are commonly sold under the brand names Anadin Extra in the UK and Excedrin in the U.S. In 2019 approximately 13.1 million units of Excedrin Migraine were sold in the United States. This application brief describes the use of an ES Industries Epic C18 column for the analysis of acetaminophen, aspirin and caffeine in accordance with the official Acetaminophen, Aspirin and Caffeine Tablets United States Pharmacopeia (USP) method for the assay.