Roudoukou (Nutmeg): Strengthening the Spleen and Stopping Diarrhea
As early as the Western Han, overseas spices and medicines flowed continuously into China via the Silk Road and sea routes; these were gradually accepted by Chinese physicians and eventually merged into the Chinese medical family as part of the materia medica. Such herbs were collectively called "sea medicines" (haiyao), meaning they all came from overseas. Li Xun of the Five Dynasties even compiled a Haiyao Bencao (Materia Medica of Sea Medicines), recording medicines from overseas and southern lands. Chinese medicine has never been closed to the outside; it has always valued foreign herbs.Roudoukou (nutmeg) was one of these imported medicines. Written records in China date to the Western Jin; Guo Yigong's Guangzhi of the Western Jin records nutmeg, noting it "grows in Thailand and Kunlun." This record is slightly wrong: nutmeg is a tropical/subtropical plant mainly produced in Malaysia, Indonesia, the West Indies, and Sri Lanka; China has introduced it in Taiwan, Guangdong, and Yunnan, but yields are low. Even now medicinal nutmeg is mostly imported. Ancient "Kunlun" lands were unlikely to produce nutmeg, but such spices first entered China indeed via the northwest Silk Road, so Guo Yigong may have heard it secondhand and mistakenly thought Kunlun produced it.Medicinal nutmeg is the kernel of Myristica fragrans (Myristicaceae). Nutmeg first entered China not as a medicine but as a spice. Adding nutmeg or its powder to food makes it more fragrant and tasty and improves digestion. Besides, nutmeg shows good pain-relieving, antiemetic, and antidiarrheal functions.Thus Chinese physicians soon incorporated nutmeg into the Chinese-medicine system, and by TCM theory summarized its properties as acrid, slightly bitter, warm, entering the spleen, stomach, and large-intestine meridians, with the actions of warming the middle and astringing the intestines, moving qi and digesting food. It treats deficiency diarrhea, cold dysentery, abdominal distending pain, poor appetite and vomiting, and undigested food. Nutmeg entered Chinese bencao works—not only Li Xun's Haiyao Bencao but many others, such as Kaibao Bencao, Waitai Miyao, Tangye Bencao, Yaoxing Lun, and Bencao Xinxian. Kaibao Bencao notes: "It is round and small, with a tight, thin purple skin; the kernel is acrid. It grows in Hu lands; the Hu name is jialule." At that time, Hu merchants brought nutmeg to China to exchange for Chinese silk and porcelain, profiting in the trade.Though nutmeg is a true "import" (Chen Zangqi said: "It comes only on large ships; China has none"), through study and application by successive Chinese physicians its use has long been localized and deeply Chinese. Generations of TCM practitioners developed deep understanding of its properties and, through TCM compatibility theory, combined nutmeg with other herbs into many classic formulas. For example, the antidiarrheal patent medicine Sishen Wan consists of nutmeg, Buguzhi (Psoralea), Wuweizi (Schisandra), and Wuzhuyu (Evodia); it has remarkable efficacy for persistent slippery diarrhea from chronic spleen cold and for five-dawn (cock-crow) diarrhea.Traditional Chinese medicine mainly uses nutmeg to strengthen the spleen and stop diarrhea, treating various dyspepsia patterns, but also recognized that nutmeg is not only useless but harmful for patients with damp-heat diarrhea/dysentery and yin deficiency with flaming fire. Bencao Congxin summarizes: "Treats heart and abdominal distending pain, stops cholera, regulates spleen-stomach deficiency cold, can digest retained food, specifically warms and supplements pericardium fire; hence it also enters the danzhong and stomach channels. But it can only stop diarrhea of lower-cold, not dysentery of lower-heat." Ancient doctors thus clearly understood nutmeg's indications and contraindications. But some doctors held that with proper compatibility, nutmeg can also treat damp-heat dysentery—for example, Ye's Luyan Fang combines nutmeg with the bitter-cold Huanglian (Coptis) for red-white dysentery from zang-fu deficiency cold with uncleared intestinal damp-heat.Most TCM practitioners still hold nutmeg should mainly treat deficiency-cold diarrhea and dysentery. For deficiency-cold diarrhea, nutmeg may be combined with spleen-strengthening Renshen (ginseng), Baizhu (Atractylodes), Shanyao (Dioscorea), Biandou (Dolichos), Yiyiren, and Gancao; with qi-moving Houpo (Magnolia bark), Muxiang (Aucklandia), Sharen (Amomum), and Jupi (tangerine peel); or with digesting Maiya (barley sprout), Shanzha (hawthorn), Laifuzi (radish seed), and Shenqu (medicinal leaven). If deficiency-cold is severe, pair nutmeg with Fuzi (Aconite), Rougui (cinnamon), Shengjiang (fresh ginger), Ganjiang (dried ginger), Gaoliangjiang (lesser galangal), Dingxiang (clove), and Hujiao (pepper); for diarrhea with abdominal pain, add Yingsuqiao (poppy shell), Baishao, and Wuzeigu (cuttlebone).Nutmeg has always been used in small doses; it is generally not decocted but made into pills, powders, plasters, and pellets. This relates partly to nutmeg being an expensive imported herb and partly to its toxicity—overdose causes poisoning. Studies show 7.5 g of nutmeg powder causes dizziness, convulsions, pupil dilation, even delirium and coma; larger amounts can kill.Modern pharmacology shows nutmeg excites gastrointestinal smooth muscle and has anti-inflammatory and sedative effects. Some studies show certain anti-tumor action: animal experiments show nutmeg inhibits mouse cervical cancer induced by 3-methylcholanthrene and markedly suppresses skin papillomas induced by dimethylbenzanthracene.Cancer patients with intractable diarrhea during chemotherapy, radiotherapy, or targeted therapy may use nutmeg as dietary therapy: adding a little nutmeg powder to food stops diarrhea and improves appetite. They may also take nutmeg-containing patent medicines like Sishen Wan or Roudou Sishen Wan for diarrhea.