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.
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.
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.
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".
Source date: 650 AD
Number of ingredients: 4 herbs
Key actions: Treats severe fevers and Heat in the Blood system. Removes Blood Stagnation.
Because it is a formula often recommended to treat the pattern 'Heat in the Blood' of which black and tarry stools is a symptom.
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.