In the early 1950s, a pharmacologist named Stewart Adams was working at Boots Pure Drug Co. in England. He was tasked with finding new treatments for rheumatoid arthritis and in 1956, he was joined by chemist John Nicholson. Contemporary treatments were either toxic or came with too many negative long-term effects. Asprin was the preferred alternative of the day, but it still carried a risk of gastrointestinal problems or allergic reactions. Adams and Nicholson began by testing compounds in aspirin, then moved on to investigating propionic compounds. They landed on 2-(4-isobutylphenyl) propionic acid, later called ibuprofen, which they tested on Adams himself. Adams and Nicholson were able to demonstrate that ibuprofen was safer and more effective than many previous pain relievers and that long-term use could effectively treat rheumatoid arthritis without significant side effects. In 1969, ibuprofen was made available by prescription in the United Kingdom as Brufen. It became available in the United States as Motrin in 1974. It debuted in the United States as Advil and became an over-the-counter drug in the 1980s. It was approved as the over-the-counter drug Nurofen in the United Kingdom that same decade. Today, ibuprofen appears on the World Health Organization’s Model List of Essential Medicines and is the most widely available non-steroidal anti-inflammatory drug in the world.