A variety of diseases could cause persistent low grade fever, which normally refers to the body temperature ranges from 37.3℃ to 38℃. In comparison, normal body temperature ranges from 36℃ to 37 ℃. Moreover, it tends to be consistent for at least two weeks. In this sense intermittent fever is different from it. In terms of herbal remedies for this specific symptom alone, there are a few optional excellent Chinese herbs available out there. Among them, Bai Wei (Swallowwort Root) is one of the best choices.
What is a persistent low grade fever?
There are a lot of causes for this prolonged symptom. Some have been found out but some others still remain unknown. The known causes are diseases like rheumatism (wind-damp in TCM), tuberculosis, chronic inflammation, and low immunity. In addition, long-term psychological stress and emotional instability could also lead to malfunction of the temperature regulating center, which is considered the culprit of unknown fever. The vulnerable groups are the elderly, infant, toddler, children, and adults sometimes.
Actually problems in any body systems could result in chronic condition. To be honest, the causes are very difficult to be located through routine examinations like blood, urine and stool. For example, in some cases caused by bacterial infection, it needs to be found out only through bacteria culture. Abuse of drugs definitely is not a good idea once this symptom is spotted. Actually this symptom itself is the response from the human body to fight against the attack of illness. As is well known, only a strong, healthy body may have this kind of amazing response to signal the master that there is something wrong happening inside. TCM wise, it is also called a tug of war between the vital energy and the pathogenic factors. When the vital energy (Yang) is weak for some reasons, the negative side (Yin) now has the upper hand – unbalance thus is created. So to speak, the essential of herbal remedies is to help restore that balance again.
Taking antipyretics at will is not recommended as it would create misconception to doctors’ diagnosis. Likewise, a single herb is seldom given according to this specific symptom in TCM practice. Instead it needs to prescribe the tailored formula after taking all the factors into consideration. Otherwise, abuse of antipyretics might lead to risks such as deceasing white cell counts and aplastic anemia. Regularly antipyretics should not be used until body temperature is above 38℃. Else, it is also one of possible early warning signs for some malignant tumors and bacterial infections, in which an overall check is highly suggested.
What is Bai Wei or Swallowwort Root?
Also known as Radix Cynanchi Atrati, it refers to the dried root or tuber of Cynanchum atratum Bge and Cynanchum versicolor Bge.
Cynanchum atratum Bge and Cynanchum versicolor Bge
The plant of Cynanchum atratum Bge is perennial herb, 40 to 70cm high, and with milky sap. The rhizome is short and with most long thin strip roots in clusters. The stems are erect, usually unbranched, and densely gray-white pubescent. Leaves are opposite, shortly stipitate, ovate or ovate-elliptic, 5 to 10cm long, and 2.5 to 7cm wide. The flowers are inflorescences umbellate, axillary, dark purple, and 1 to 1.5cm in diameter. Most seeds are in ovoid shape, narrowly winged, and white long woolly-like pilose. Florescence is from May to July and fruiting time is from August to October. Usually it grows in mountain slopes or woodsides.
Cynanchum versicolor Bge looks like Cynanchum atratum Bge. But it is with the sprawling stem, shortly pubescent, and ovate or elliptic-lanceolate leaf blade. The flowers are smaller, 1cm in diameter, yellowish green in early bloom and black purple later. Usually it grows in mountainous regions.
Property and indications
From the perspective of Traditional Chinese Medicine (TCM), it is deemed as bitter, salty, cold, and nonpoisonous in nature. And it covers meridians of stomach, lung and kidney.
Main functions are to clear heat, cool blood, promote urination, treat stranguria, relieve toxicity accumulated by internal heat, and cure boils. Main clinical usage and indications are fever due to impaired Ying blood by warm pathogenic factor, fever of deficiency type, heat that feels like comes from the bones caused by consumption, coughing up blood due to lung heat, postpartum fever caused by blood deficiency, persistent low grade fever for no reason, sleepiness due to wind-warm scorching heat, difficulty in urination or blood urine caused by heat, swollen and painful throat, toxic ulcers, snakebite, and pyogenic infections.
Regular dosage is 4.5 to 9 grams.
Possible side effects and contraindications
The root of Cynanchum atratum Bge contains essential oil and cardiac glycoside. Main ingredient of the essential oil is Cynanchol, which has strong cardiotonic effect. In overdose of 30 to 40 grams, it may lead to toxic reactions similar to cardiac glycoside, such as palpitation, nausea, sickness, dizziness, headache, diarrhea, and drooling. TCM wise, according to Ben Cao Jing Ji Zhu (Collected Annotation of Herbalism), it is incompatible with Huang Qi (Astragalus Root), Da Huang (Rhubarb), Da Ji (Root of Beijing Euphorbia), Gan Jiang (Dried Ginger Root), Gan Qi (Dried Lacquer), Da Zao (Chinese Date, Jujube), and Shan Zhu Yu (Asiatic Cornelian Cherry Fruit).
Herbal formulas for constant low grade fever and others
(1). Zhu Pi Da Wan, from Jin Gui Yao Lue (Synopsis of Golden Chamber), is used for postpartum fever due to blood deficiency, fatigue, irritation, vomit, and belch. The individual herbs are Bai Wei, Zhu Ru (Bamboo Shavings), Shi Gao (Gypsum), Gui Zhi (Cinnamon Twig), and Gan Cao (Licorice Root).
(2). According to Nan Jing Chang Yong Zhong Cao Yao (Frequently Used Medicinals of Nanjing), there is a formula consisting of Bai Wei, Lu Cao Guo (Humulus Fruit), and Di Gu Pi (Wolfberry Root Cortex), which is used for hot flash caused by phthisis. And another one for urinary infection is composed of Bai Wei and Che Qian Cao (Herba Plantaginis).
(3). According to He Bei Zhong Yao Shou Ce (The Clinical Handbook of Chinese Medicinals in Hebei), the formula of Bai Wei and Di Gu Pi is exclusively for treating prolonged low grade fever caused by deficiency and night sweat.