Yes blueberries can make your poop turn blue.
If you eat blueberries the blue color in the poop can make your poop turn blue which is normal.
Eating other foods that are blue or contain blue dye can also cause your poop to turn blue.
Blue poop is not always bad although in some cases blue poop may be a sign of digestive issues or bowel issues.
But in most cases blue poop is simply a result of something you ate such as blueberries, food with blue dye etc.
If the blue poop does not clear up within a week or so or it gets darker blue then you should see a doctor but most times blue poop or different colors of poop are harmless.
Healthy poop should appear as and look like a sausage or log with a smooth surface and be relatively easy to pass and be brown in color.
However healthy poop can be either brown or even green in color and still be healthy.
A healthy poop, should reflect a mixture of all the colors of the food you eat and that bile.
Almost any shade of brown, or even green, is considered OK.
Normal poop color is brown.
This is due to the presence of bile in the stool.
Normal poop color can range from light yellow to brown to almost black.
However if your poop is red, maroon, black, clay-colored, pale, yellow, or green this may signify a problem.
Bile from the liver creates the typical brown hue of a healthy bowel movement.
When the poop is very pale, it often means that not enough bile is reaching the poop.
Problems with the gallbladder, pancreas, or liver are reasons why poop may not contain enough bile.
Normally poop should be brown, have a peanut-butter texture, and look like a sausage.
If you have abnormal colors, it may be due to something you ingested.
But it may also be due to serious illness.
If it's abnormal once, it's likely nothing to worry about.
Symptoms of an intestinal blockage include severe belly pain or cramping, vomiting, not being able to pass stool or gas, and other signs of belly distress.
Floating poop is often an indication of high fat content, which can be a sign of malabsorption, a condition in which you can't absorb enough fat and other nutrients from the food you're ingesting.