What does milk have in common with blood? According to Kou Zongshi (fl. 1110-1117), author of Bencao yanyi (Extended Interpretations on Materia Medica), they are basically the same vital fluid produced by the female body at two critical moments in a woman’s life. While the first menstrual period signifies the maturation of reproductive power, motherhood is the consummation of that power–miraculously causing the vital fluid to flow upward as milk. After nursing ends, the flow of milk again reverses back to blood, as evident from the return of the menses.
“Human milk.” Anon. Buyi Leigong paozhi bianlan (n.p, 1591), Book 8.
For centuries, Kou’s comment was repeatedly quoted as the dominant theory over lactation in the realm of learned medicine. It also coincides with parallel attempts to speculate on the metaphysical foundation of sex differences in women, and the consolidation of women’s medicine (fuke) and pediatrics (erke) as medical specialties.
However, Kou’s original aim was to make sense of medical recipes. In particular, he was trying to figure out why do so many recipes for eye medicine use human milk to mix up powdered mineral drugs: a practice that has parallels in different cultural contexts. Since blood is essential for the five senses to function and human milk is essentially blood, Kou reasoned, this makes it an excellent medicine for eye diseases. Another recipe that may have been on his mind is the recommendation to drink “three portions of human milk” to help with obstructed menses. It makes sense if they were considered of the same origin. Like cures like.
Let’s pause here to consider what this means. Working with Chinese materia medica texts often means untangling different strands of thought, modes of compilation and miscellaneous quotations. The entry on each substance (e.g. human milk, renru or ruzhi) often begins with a learned survey of previous literature, including passages from classical literature and histories, and ends with a large (and often unwieldy) body of recipes. The problem is that the prescribed uses of the substances in the first part do not always sit well with the recipes, which are messy, opaque, and often outright strange.
In fact, Kou Zongshi’s work could be understood as a scholar-physician’s attempt to impose order and coherence on the unruly recipes, which were becoming increasingly available in print.  The incongruities and tension between theory and recipes, however, allows us to follow the intricate dance between empiricism and rationalism in such texts: when did authors equate recipes with real-life experiences, and when did they treat them as exemplars of theory and formulaic principles? When did book culture begin to shape the ways in which medicines were prepared, consumed, and invented?
Back to Kou Zongshi’s ingenious, if somewhat contrived, speculation over the nature of lactation. It did not seem to have caught much attention immediately. The twelfth and thirteenth centuries witnessed a growing suspicion among medical experts to discipline and curb wet nurses’ sway over childcare, and pediatric treatises abound with warnings against drunken, naughty wet nurses whose milk turns unwholesome to the infant. Again, the female body’s power to nourish but also intoxicate with her transformed milk resonates with similar discourses discussed elsewhere on this blog; notably, alcoholic drinks were seen to be a bad thing that excites her passions, in contrast to ancient Roman recommendations.
In addition, the conquest of Mongols brought about increased consumption of cow and goat’s milk. A leading physician active in the fourteenth century advised consuming those over human milk, which is easily “tainted with poisonous passions.” It looks like the arrival of more abundant dairy products would transform the existing pharmacopeia once and for all.
But not so simple. By the sixteenth century in China, human milk had become a “super food” of sorts, especially among elite families. Kou Zongshi’s dusty theory became a dominant trope, fanning the imagination of the female body as a machine of alchemical wonders, and her milk a sort of elixir that revitalizes the frail and depleted bodies. In the sixteenth-century encyclopedia Systematic Materia Medica(Bencao gangmu), Li Shizhen, the erudite naturalist and capable physician, criticized the excessive fetishizing of human milk. The prudent Li nevertheless included twelve “new recipes” that involve human milk as medicine. Li’s encyclopedia was first printed in 1596; soon after the turn of the century, dietary manuals began to teach people how to prepare dried milk powder at home, after collecting fresh milk from “strong women who just gave birth to boys”. Presumably, women sold their milk not as wet nurses, but directly to pharmacists (as depicted in the picture above).
So did people in imperial China consume human milk as medicine? Quite likely. But was it ubiquitous? Probably not. Recipes can be practical and fantastic, and theorists can explain and inspire. What matters is that human milk as medicine gradually came to be taken out of the context of nursing and acquired a more abstract quality as commodity.
 Charlotte Furth, A Flourishing Yin: Gender in China’s Medical History: 960–1665 (Berkeley, CA: University of California Press, 1999).
 Asaf Goldschmidt, The Evolution of Chinese Medicine: Song Dynasty, 960-1200 (London ; New York: Routledge, 2009).
 Ping-Chen Hsiung, “To Nurse the Young: Breastfeeding and Infant Feeding in Late Imperial China,” Journal of Family History, 20, 3 (1995), pp. 217-38.
 Paul D. Buell, E.N. Anderson, and Charles Perry, A Soup for the Qan : Chinese Dietary Medicine of the Mongol Era as Seen in Hu Sihui’s Yinshan Zhengyao, 2nd Rev. and Expanded ed. (Leiden, The Netherlands: Brill, 2010).