The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
Black and tarry stools can be the consequence of several so-called “patterns of disharmony” in Chinese Medicine.
Chinese Medicine sees the body as a system, not a sum of isolated parts. A "pattern" is when the system's harmony is disrupted, leading to symptoms or signs that something is wrong (like black and tarry stools here). It is similar to the concept of disease in Western Medicine but not quite: a Western disease can often be explained by several Chinese patterns and vice-versa.
A pattern often manifests itself in a combination of symptoms that, at first glance, do not seem necessarily related to each others. For instance here black and tarry stools is often associated with fever and delirious speech in the pattern “Heat in the Blood”.
Once identified, patterns are treated using medicinal herbs, acupuncture, and other therapies. In the case of black and tarry stools we’ve identified that a herbal formula called Xi Jiao Di Huang Tang can help treat the patterns behind the symptom.
Heat in the Blood, a "pattern of disharmony" that can cause black and tarry stools
In Chinese Medicine black and tarry stools is a symptom for the pattern "Heat in the Blood". Below is a small explanation for it with links for more details.
Water Buffalo Horns (Shui Niu Jiao) is the king ingredient for Xi Jiao Di Huang Tang, a formula used for Heat in the Blood
Heat in the Blood
Pulse type(s): Rapid (Shu)
Tongue color: Red
Heat in the Blood (or Blood-Heat) refers to a condition whereby Heat, as a so-called "Pernicious Influence", entered the Blood. This invasion tends to accelerate Blood flow (leading to a faster pulse) and to manifest itself in various types of bleeding as well as other symptoms.
In addition to black and tarry stools, other symptoms associated with Heat in the Blood include fever and delirious speech.
From a Western Medicine standpoint Heat in the Blood is associated with health issues such as Early Menstruation, Abnormal Uterine Bleeding or Heavy Menstruation.
Heat in the Blood is often treated with Xi Jiao Di Huang Tang, a herbal formula made of 4 herbs (including Water Buffalo Horns - Shui Niu Jiao - as a key herb). Xi Jiao Di Huang Tang belongs to the category of "formulas that clear nutritive-level heat", which might be why it is often recommended for this pattern. Its main action as a formula is: "Treats severe fevers and Heat in the Blood system".
A herbal formula that might help with black and tarry stools
Xi Jiao Di Huang Tang
Source date: 650 AD
Number of ingredients: 4 herbs
Key actions: Treats severe fevers and Heat in the Blood system. Removes Blood Stagnation.
Why might Xi Jiao Di Huang Tang help with black and tarry stools?
Because it is a formula often recommended to treat the pattern 'Heat in the Blood' of which black and tarry stools is a symptom.
Other symptoms characteristic of Heat In The Blood include fever and delirious speech.
Water buffalo horn might help with black and tarry stools
Why might Water Buffalo Horn (Shui Niu Jiao) help with black and tarry stools?
Because it is a key herb in Xi Jiao Di Huang Tang, a herbal formula indicated to treat the pattern 'Heat in the Blood' (a pattern with black and tarry stools as a symptom)
Water Buffalo Horns is a Cold herb that tastes Bitter and Salty. It targets the Stomach, the Heart and the Liver.
Its main actions are: Cools the Blood, drains Fire and stops reckless movement of Blood. Clears Heat and Fire and stops tremors and convulsions. Cools Fire and expels toxins.