You have diarrhea if you’re passing three or more loose or watery stools per day, or significantly more often than what’s normal for you personally. The key factor isn’t just frequency. Passing several well-formed stools in a day isn’t diarrhea, and a single loose stool doesn’t qualify either. It’s the combination of loose consistency and increased frequency that defines it.
What Diarrhea Actually Looks Like
The most reliable way to identify diarrhea is by stool consistency, not just how often you’re going. The Bristol Stool Chart, a visual tool used in clinical settings, classifies stools into seven types. Types 6 and 7 are considered diarrhea: Type 6 is mushy with fluffy, ragged edges, and Type 7 is entirely liquid with no solid pieces at all.
If your stools are soft but still hold a shape, that’s generally not diarrhea. The distinction matters because diet changes, coffee, or a stressful morning can all send you to the bathroom more often without actually causing diarrhea. What you’re looking for is stool that’s lost its form, is watery or mushy, and is happening at least three times in a day.
Symptoms That Come With It
Loose stools rarely show up alone. Most episodes of diarrhea come with abdominal cramping, a sense of urgency (needing to get to a bathroom fast), bloating, or nausea. If an infection is causing it, you may also have vomiting, fever, or body aches. These accompanying symptoms can actually help you distinguish true diarrhea from a one-off loose stool caused by something you ate.
The sensation of urgency is particularly telling. With normal bowel movements, you feel the need to go but can comfortably wait. With diarrhea, the urge is often sudden, intense, and hard to delay.
Acute vs. Chronic Diarrhea
Diarrhea that lasts less than 14 days is considered acute. This is the most common type, usually caused by a viral or bacterial infection, food that didn’t agree with you, or a short course of medication. Most acute episodes resolve on their own within a few days.
Diarrhea lasting longer than two weeks is classified as chronic or persistent. At that point, something beyond a simple stomach bug is likely going on. Chronic diarrhea can signal food intolerances, inflammatory bowel conditions, celiac disease, or other digestive issues that benefit from medical evaluation. The two-week mark is the clearest signal that your body isn’t resolving this on its own.
How to Tell in Babies and Infants
Identifying diarrhea in babies, especially breastfed ones, is tricky. Normal breastfed stools are already loose, runny, and seedy. They’re typically yellow but can be green (that’s just bile, and it’s normal). Runny stools in breastfed babies can even have a water ring around them on the diaper, and that’s still within normal range.
The signs that a baby actually has diarrhea include a sudden increase in stool frequency, stools that contain mucus or blood, stools that smell noticeably worse than usual, and a baby who’s eating poorly, acting sick, or running a fever. If the change persists for three or more stools, that’s the threshold. In terms of severity: 3 to 5 watery stools per day is mild, 6 to 9 is moderate, and 10 or more is severe.
Severity and Dehydration Risk
The biggest concern with diarrhea isn’t the diarrhea itself. It’s fluid loss. Your body absorbs most of its water through the intestines, and when stool moves through too quickly, that absorption doesn’t happen. More than 10 bowel movements a day, or losing fluids faster than you can drink them, puts you at risk for dehydration.
Signs of dehydration in adults include excessive thirst, dry mouth and skin, dark-colored urine, very little urination, dizziness, lightheadedness, and severe weakness. In children, the signs are different: no wet diaper for three or more hours, crying without tears, a dry mouth or tongue, unusual sleepiness or irritability, and sunken-looking eyes, cheeks, or abdomen. One quick check for children is to gently pinch the skin. If it doesn’t flatten back down right away, that suggests dehydration.
When It Needs Medical Attention
For adults, diarrhea that hasn’t improved after two days, a fever over 102°F (39°C), bloody or black stools, severe abdominal or rectal pain, or signs of dehydration all warrant a call to your doctor. Six or more loose stools per day also crosses the threshold for getting professional guidance.
For children, the timeline is shorter. Diarrhea lasting more than 24 hours, any fever in infants, refusal to eat or drink for more than a few hours, or bloody stools should prompt a call. Infants under 12 months, premature babies, and children with existing medical conditions need earlier attention than otherwise healthy older kids.
Certain groups are also more vulnerable to complications from diarrhea regardless of severity: pregnant people, adults over 65, anyone currently on antibiotics, and those with weakened immune systems. For these groups, staying in touch with a doctor even during what seems like a mild episode is a reasonable precaution.