Is Black, Tar-Like Stool Normal After Emergency Gastric Lavage?

Bowel movement after emergency gastric lavage?

Hello, I was admitted to the emergency room a couple of days ago for gastric lavage and had activated charcoal administered via a nasogastric tube.
Since then, I have had two bowel movements, both of which were black, tarry stools.
Is this situation normal, doctor? Thank you.

K, 30~39 year old female. Ask Date: 2023/12/29

Dr. Lin Minghui reply Gastroenterology and Hepatology

The stool may appear black after gastric lavage with activated charcoal, which is generally considered normal due to the color of the charcoal.
Activated charcoal can adsorb toxins in the stomach and is not absorbed by the body, ultimately being excreted in the stool, thereby alleviating poisoning.
Clinically, patients may experience gastrointestinal discomfort or constipation as side effects after use, so please monitor for any discomfort.
Best wishes for your health!

Reply Date: 2023/12/29

More Info

After undergoing an emergency gastric lavage, especially with the use of activated charcoal via a nasogastric tube, it is not uncommon to experience black, tar-like stools. This phenomenon is primarily due to the activated charcoal itself, which can cause the stool to appear dark. Activated charcoal is often used in cases of poisoning or overdose because it binds to toxins in the gastrointestinal tract, preventing their absorption into the bloodstream. However, it can also lead to the formation of black stools as it passes through the digestive system.

The presence of black, tarry stools, medically known as melena, can also indicate gastrointestinal bleeding, particularly from the upper gastrointestinal tract, such as the stomach or duodenum. The blood that is digested in the gastrointestinal tract can turn black and have a tar-like consistency. However, in your case, since you have recently undergone gastric lavage and received activated charcoal, it is likely that the black stools are a result of the charcoal rather than bleeding.

It is important to monitor your symptoms closely. If the black stools persist beyond a few days, or if you experience additional symptoms such as abdominal pain, dizziness, weakness, or any signs of active bleeding (such as bright red blood in your stool or vomiting blood), you should seek medical attention immediately. These could be signs of a more serious condition that requires further evaluation.

In terms of the timeline for your stools to return to a normal color, this can vary. Typically, once the activated charcoal is fully cleared from your system, which may take a few days depending on your gastrointestinal transit time, your stools should gradually return to their normal color. Staying hydrated and maintaining a balanced diet can help facilitate this process.

If you continue to experience black stools for an extended period or have concerns about your gastrointestinal health, it would be wise to follow up with your healthcare provider. They may recommend further diagnostic tests, such as a stool test for occult blood, to rule out any underlying issues.

In summary, while black, tar-like stools can be a normal occurrence after the use of activated charcoal, it is crucial to remain vigilant for any concerning symptoms that may indicate a more serious problem. Always consult with your healthcare provider if you have any doubts or if your symptoms change.

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