Reddish-brown stool is most often caused by something you ate. Beets, tomatoes, cherries, red gelatin, and foods with red artificial dyes can all tint your stool a noticeable reddish-brown that looks alarming but is completely harmless. In some cases, though, that color comes from a small amount of blood mixing with normal brown stool, which deserves a closer look.
Foods That Turn Stool Reddish Brown
Beets are the most common culprit. They contain a red pigment called betanin that’s intense enough to survive digestion and give stool a blood-red or reddish-brown appearance. The effect can last one to three bowel movements after eating them, and it sometimes shows up in urine too. Tomatoes, cherries, cranberries, red peppers, and tomato-based sauces can do the same thing, especially in larger quantities.
Artificial food coloring is another frequent cause. Red frosting, candy, fruit punch, and red-dyed snacks can pass through your digestive system with enough pigment intact to shift your stool color. If you ate something with vivid red dye in the past 24 to 48 hours, that’s likely your answer. The color change should resolve once the food works its way through.
How Blood Changes Stool Color
Normal stool gets its brown color from bile, a digestive fluid your liver produces. When blood enters the mix, the resulting color depends on where the bleeding starts. Bright red blood typically comes from the lower digestive tract: the rectum, anus, or lower colon. Reddish-brown stool often means the blood originated slightly higher up, giving it more time to partially break down during digestion but not enough time to turn fully dark.
Blood from much higher in the digestive tract, like the stomach or upper intestine, gets broken down so thoroughly by digestive enzymes that it turns black and tar-like rather than red. So reddish-brown sits in between: it suggests the source is somewhere in the mid to lower intestine, or that a lower source is producing enough blood to mix visibly with stool.
Common Medical Causes
Hemorrhoids are the most frequent non-dietary reason for red or reddish-brown stool. These are swollen veins in the anus or lower rectum, similar to varicose veins. They often bleed during bowel movements, leaving bright red streaks on the stool or toilet paper. Straining, sitting for long periods, and constipation all make them worse.
Anal fissures, which are small tears in the lining of the anus, cause a similar appearance. They typically happen after passing a hard or large stool and tend to cause sharp pain along with the bleeding. Both hemorrhoids and fissures are very common and usually heal on their own or with simple at-home care.
Colon polyps are small growths on the lining of the colon. Most are harmless, but some can bleed intermittently, producing reddish-brown stool that comes and goes without an obvious dietary explanation. Some polyps can become cancerous over time if not removed, which is one reason routine screening matters.
Inflammatory Bowel Conditions
Ulcerative colitis and Crohn’s disease both cause inflammation in the digestive tract that can lead to bloody stool. In ulcerative colitis, the hallmark symptom is diarrhea mixed with blood, mucus, or pus. You’d also typically notice urgency to use the bathroom, frequent loose stools, cramping, and fatigue. These symptoms tend to develop gradually over weeks rather than appearing suddenly after a single meal.
If your reddish-brown stool is a one-time event and you feel fine otherwise, inflammatory bowel disease is unlikely. But if you’re seeing blood repeatedly, especially alongside diarrhea, abdominal pain, or unintended weight loss, those symptoms together paint a different picture.
Medications and Supplements
Iron supplements commonly change stool color, but they typically produce dark green or matte black stool rather than reddish-brown. The iron oxidizes in your gut, creating a dark pigment that appears within a day or two of taking a dose. This is harmless and looks noticeably different from blood: iron-related dark stool has a dry, coarse texture and normal odor, while stool darkened by actual bleeding tends to be sticky, tar-like, and distinctly foul-smelling.
Bismuth-based medications (the active ingredient in Pepto-Bismol) also darken stool to black. Antibiotics can occasionally shift stool color as well. If you started a new medication recently and your stool color changed around the same time, that connection is worth noting.
A Simple Way to Check at Home
If you suspect food is the cause, try eliminating the likely culprit for two to three days. Beets, tomato sauce, and red-dyed foods are the usual suspects. If your stool returns to its normal brown, you have your answer.
For ongoing concern, a fecal immunochemical test (FIT) can detect hidden blood in stool that isn’t visible to the eye. Unlike older stool tests that required dietary restrictions for three days beforehand (because they could react to red meat and certain raw fruits and vegetables), the FIT test uses antibodies specific to human blood, making it more reliable with fewer false positives. Your doctor can provide one, and some are available over the counter.
Signs That Need Prompt Attention
A single episode of reddish-brown stool after eating beets or red candy is nothing to worry about. But certain accompanying symptoms change the urgency. Seek emergency care if you notice large amounts of blood, lightheadedness, a rapid heart rate, or sudden weakness, as these can signal significant blood loss.
Other symptoms worth getting evaluated include:
- Abdominal pain or persistent cramping
- A change in bowel habits lasting longer than four weeks
- Narrow or thin stools
- Unintended weight loss
- Fever alongside bloody stool
- Fatigue that doesn’t improve with rest
Current guidelines recommend colorectal cancer screening starting at age 45 for people at average risk, even without symptoms. If you’re in that age range and haven’t been screened, reddish-brown stool is a reasonable prompt to get it scheduled, regardless of whether the color turns out to be from last night’s beet salad.