Stool Color Chart: What Poop Colors Mean and Why

When you glance in the toilet, color is one of the fastest signals your body gives you. Brown is the normal color, and most other shades come from something simple like yesterday’s meal, a supplement, or a medicine. A few colors, though, are worth a second look. Use this stool color chart to see why stool is brown, what changes it, what each color usually means, and when a color is a red flag rather than a leftover from dinner.

Why stool is normally brown

Your liver makes bile to help digest fats, and it flows into your small intestine with each meal. As bile moves through your gut, bacteria and enzymes break it down into pigments, mainly one called stercobilin, which gives stool its familiar brown shade.

Healthy stool ranges from light tan to deep brown depending on your diet and how fast things move through you. Small day-to-day shifts within brown are normal. Because brown depends on bile being made, released, and broken down normally, a steady brown is a quiet sign that this whole system is working.

What affects stool color

Several everyday factors can shift the color away from brown:

• Food and dyes. Leafy greens, beets, blueberries, black licorice, and brightly colored or artificially dyed foods can tint stool green, red, or very dark.
• Iron supplements. Iron commonly turns stool dark, sometimes nearly black. This is a known, harmless effect, though it can look similar to true bleeding.
• Medications. Some medicines, including certain antacids that contain bismuth, can darken stool, and bismuth-based products may even turn it black.
• Antibiotics. By changing the balance of gut bacteria that process bile, antibiotics can sometimes leave stool greener than usual.
• Faster transit. When stool moves through quickly, as during diarrhea, bile has less time to be fully broken down, so stool can come out green or yellow.

A color change that lines up with a new food, supplement, or medicine, and that fades once it passes or you stop, is usually nothing to worry about. Most diet-driven changes clear within a day or two.

Stool color chart: color by color

Green: usually harmless

Green stool often comes from leafy greens, green food coloring, antibiotics, or food moving through the gut quickly so that bile has not finished breaking down. On its own, with no other symptoms, green is generally nothing to worry about and passes on its own.

Yellow or greasy: watch if it repeats

An occasional yellow stool is common. But yellow stool that looks greasy, smells especially foul, and is hard to flush can mean your body is not absorbing fat well. A single episode is usually not a concern. If greasy yellow stool keeps happening, mention it to a doctor.

Black or tarry: take seriously

Black, sticky, tar-like stool can come from harmless sources like iron supplements or bismuth-containing medicines. But it can also mean bleeding higher up in the digestive tract, where blood darkens as it travels down. If you are not taking iron or bismuth, treat black tarry stool as urgent.

Red or bloody: get it checked

Bright red can come from beets or red food coloring and clear quickly. It can also be blood from lower in the gut, the rectum, or hemorrhoids. Streaks on the surface of the stool or blood in the toilet water are worth attention, and a doctor should sort out the cause rather than you guessing.

Pale or clay-colored: not normal

Stool that is pale, gray, or clay-colored can mean little or no bile is reaching your gut, which may reflect a problem with the bile ducts or liver. A one-off can follow certain medicines, but stool that stays pale should be checked.

When to see a doctor

Most color changes are harmless and fade within a day or two once the food or supplement behind them passes. Some, though, are red flags that deserve prompt medical attention:

• Black, tarry stool, especially if you are not taking iron or bismuth, or bright red or bloody stool. Contact a doctor right away, since both can signal bleeding in the digestive tract.
• Stool that stays pale, gray, or clay-colored, which can reflect a bile duct or liver issue.
• Greasy yellow stool that keeps coming back.

This article is general information, not medical advice, so let a clinician interpret any warning sign in your own situation.

How bellySignal helps

Colors are easy to notice and just as easy to forget by your next appointment, and it is hard to remember whether last week’s color came from a meal or something more. With bellySignal you can log your Bristol stool type (1 to 7), your stool color, and any blood or mucus, alongside urine color for hydration (a 1 to 8 scale), your water intake, food triggers, and free-text notes.

Logging color next to the foods, supplements, and medicines you took makes it far easier to tell a diet-driven color from a real warning sign, and to give a doctor clear detail instead of a vague memory.

Your diary is stored on your device, and you can start logging without an account. Optional login, health platform sync, and export are available. Selected health values, including stool type, symptoms and manually entered weight, are also sent to PostHog, which is enabled by default. The analytics switch in settings controls PostHog only. Firebase Analytics receives usage events without those health values and remains active. Privacy policy.