Feeling nauseous when you need to poop is common and usually happens because the gut and the nervous system are closely linked, so signals from your bowels can trigger queasiness.

What’s going on in your body

• As your rectum and colon fill and stretch, they send signals through nerves (including the vagus nerve) to your brain; this can lower blood pressure and heart rate a bit in some people and create a wave of nausea, dizziness, or “gross” feeling.

• If you are even mildly constipated, backed‑up stool can cause bloating, cramping, and a sense of fullness that often shows up as nausea when you finally feel the urge to go.

• The same infections or irritants that speed things up (like viral “stomach flu,” food poisoning, or other gut irritation) can cause both the urge to poop and nausea at the same time.

When it’s usually harmless

It is often benign if:

• The nausea spikes right before or during a bowel movement and eases soon after.
• You are otherwise well, with no weight loss, fevers, or constant severe pain.

This pattern fits things like:

• Mild constipation with straining (triggering a vagal response and queasiness).

• Occasional gut sensitivity, IBS, or anxiety that ramps up gut–brain signaling when you feel the urge to go.

When to see a doctor

You should get checked promptly if you notice:

• Severe or worsening abdominal pain, vomiting, or a swollen/bloated hard belly.

• Blood in stool, black/tarry stool, fever, or unintentional weight loss.

• Feeling like you might faint, chest pain, or very slow/fast heartbeat when you strain, as strong vagal reactions can sometimes be more serious.

Things you can do now

• Keep stools soft: drink enough fluids, eat fiber (fruits, vegetables, whole grains), and avoid regularly “holding it” when you need to go, which worsens constipation.

• Try not to strain; give yourself time on the toilet, use a footstool to elevate your feet, and relax your belly and pelvic muscles.

• Track triggers: note if certain foods, stress, or going many hours without a bowel movement make nausea before pooping more likely, and adjust where you can.

If this is happening often or feels intense, describe the pattern (how long, how often, associated symptoms) to a clinician; they can rule out problems like significant constipation, irritable bowel syndrome, or other gut issues and suggest targeted treatment.