In 1683, a self-proclaimed apothecary physician and London professor of physick by the name of Guilelmus (William) Salmon authored a pharmacopoeia titled Doron medicum, the ‘gift of medicine’ (Greek/Latin translation). This text formulates an English supplement to the Latin Materia medica (16th century), discussing internal and external compound medicines of the late 17th century. This pharmacopoeia enabled those incapable of reading Latin to provide medical care to a challenging post-plague community. Opiology, mercury, dragon’s blood, willow bark, animal preparations and therapies now considered obscure, provide insight into therapies at the time. Early critical care treatments in haemorrhage control and pain management are described. Doron medicum preceded the controversial opening by the College of Physicians of the first London Dispensary in 1698, and was published in a maturing period of medical governance and healthcare establishment in London. During the 17th century, great competition and debate existed between the Royal College of Physicians and the apothecaries. Throughout such debates, William Salmon advocated for access to medical care for the poor and recognition of an allied approach to healthcare. This paper discusses Salmon’s contribution to medicine, which has been poorly transcribed in medical history. A selection of opiate-based analgesic therapies, early critical care strategies and animal preparations are revisited. A small chronicle of William Salmon’s life and professional achievements will be reviewed. Debate surrounding the opening of the first London Dispensary will be discussed in relation to William Salmon’s contribution, echoing ongoing contemporary challenges in healthcare over 300 years later.