Brief Answer:
Is he on any medication

Detailed Answer:
Hi

Thanks for asking on this platform

I have seen the image and do understand your concern.
Its hard and abnormally dark black.
Common cause of black and hard stool is medication(iron syrup). Other cause can be bleeding in intestinal tract but in that case it is usually semisolid and sticky.
I would like to know for how many days he is passing stool like this, is is passing normal stool in between, is he on any medication, is there any XXXXXXX blood in stool.
Please get back with the answer so that I better able to help you out.
Waiting for your reply.
Regards

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Brief Answer:
Most likely because of iron and food items

Detailed Answer:
Hi

Hard black stool is common on babies who are on iron supplement. Even the food item like spinach and beet may add to this(because of dark color).
I suggest you to hold the iron for few days. Just check the stool pattern and once it gets normalises, you may start with a lesser dose after consulting your pediatrician. Give plenty of fluids to avoid constipation.
You may continue giving spinach and beet root as these items can cause altered color of stool but not constipation.

I shall be glad to help further if you need any.

Regards

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