When talking about blood in vomit, I touched on the fact that blood doesn’t always look like blood, meaning doesn’t always have the typical bright red appearance. Fresh blood does, blood that has already been digested does not. Instead, it looks like coffee grounds.
I don’t want to freak anybody out with graphic images, so I just include illustrations. But if you want to see what that really looks like, there is an example photo here.
Couldn’t a dog just get into garbage and eat some coffee grounds?
Well, everything is possible, particularly with dogs. If that were the case, you should be able to find evidence of that quite easily. If that is the case, you might be looking at potential caffeine poisoning. Caffeine toxicity generally ranges from moderate to severe.
The symptoms of caffeine toxicity can indeed include vomiting, diarrhea, as well as hyperactivity, restlessness, high blood pressure, abnormal heart rate, tremors … and in severe cases seizures, collapse and death.
The urgency and actions you need to take depend on how much was ingested and how is your dog feeling.
Coffee grounds that are not from coffee
What appears like coffee grounds might not be coffee grounds at all but digested blood. This can be accompanied by black tarry stools. This too can be caused by a stomach ulcer, or it can be digested blood that comes from elsewhere, such as swallowed blood from the respiratory tract.
Your dog is likely to be refusing their food, lethargic and having diarrhea.
What can cause this?
The most common potential cause is damage in the GI tract; ulceration or erosion. It can happen as a result of gastritis, trauma, severe vomiting, foreign body, mass/tumor, liver disease, pancreatitis, Addison’s disease, drugs (e.g. NSAIDs, corticosteroids) and even mast cell tumors that are actually on the skin (they can release histamine etc leading to hyperacidity in the stomach).
Less likely causes are lung disorders (where blood is swallowed and the vomited) or bleeding disorders. In such cases, you’d likely see many other red flags along with vomiting coffee grounds.