Thomas Cogan and The Haven of Health: Renaissance Medicine
Cogan references many scriptures throughout his writings. In Goldwin Smith’s article, “The Practice of Medicine in Tudor England”, he explains how the church and religious leaders helped develop hospitals and rehabilitation centers.  The support of the churches was the driving factor for research, education and development of Renaissance medicine, and therefore helps us to understand why Cogan merged the scientific and secular worlds in his book: in the Renaissance, religion and science were not mutually exclusive.
Due to a lack of technology and development of antibiotics, as well as other factors, health practices and remedies were all tied to natural ingredients. Different fruits, herbs, and foods were researched and tested to treat different illnesses. Although not all of the practices described in Cogan’s The Haven of Health are still valid today, many practices have been proven with modern technology and research.
One example of a medical practice still common today is the medical use of spearmint. Cogan describes its effects as adding “comfort to the stomacke, helps digestion, stirreth vp the minde, good for teeth and gummes.” Spearmint is now used in toothpastes and mouthwashe, as it is good for the mouth. It is often offered at the end of a meal to keep the stomach calm and the spearmint oil is used in aromatherapy to treat headaches and relax the body.
Underlying the basis of Cogan's health practices, and central to the common use of herbal remedies, is the antiquated theory of humorism. Humorism dates back to the Ancient Greeks, and was a common school of thought in Renaissance Europe, especially prevalent in England. The idea of humorism is that there are four main fluids, called humors, in every body: blood, yellow bile, black bile, and phlegm. "The condition of health" is when all four humors are in perfect balance with one another. Renaissance doctors believed that an excess of one humor more than another was the cause of any physical or mental illness.  The common practice of bloodletting and cupping in order to cure a patient stems back to the idea of humors. 
The rest of Chapter 213 is dedicated to understanding the meat and drink that is best suited to each humor or period of life. However, a hot and moist temperament would be most beneficial to undertake a cold and dry diet, in order to balance out the excess of humors. Many of the health practices laid out in the rest of the book seem to fall under the idea that different kinds of temperaments require a different kind of diet. Why, then, this explanation of the humors is not placed toward the beginning of The Haven of Health is not known. Perhaps it was because the theory of temperament was well known among his readers, and it is only his idea of a person going through every temperament throughout his life that was new and unknown.
 Goldwin Smith, "The Practice of Medicine in Tudor England," The Scientific Monthly, Vol 50, No 1 (Jan, 1940), 71-72.
 Thomas Cogan. The Haven of Health: chiefly made for the comfort of students, and consequently for all those that haue a care of their health, amplified vppon fiue wordes of Hippocrates, written Epid. 6. by Thomas Cogan maister of Artes, & Bacheler of Phisicke. 1588, 38.
 "What are the health benefits of spearmint?" Medical News Today, Last modified September 8, 2014, http://www.medicalnewstoday.com/articles/266128.php
 George Sarton and Erika von Erhardt-Seibold, "Remarks on the Theory of Temperament," Isis 34, no. 3 (Winter 1943), 205.
 Gerry Greenstone, "The history of bloodletting," BC Medical Journal 52, no. 1 (January/February 2010), 12.
 Cogan. The Haven of Health, 191-192.
 David Keirsey, Please Understand Me II: Temperament, Character, Intelligence. (Del Mar: Prometheus Nemesis Book Company, 1998), 26.