Digestive symptoms

Nausea

Also called: sick feeling, queasy

Nausea is the unpleasant urge to vomit. The brain's vomiting centre integrates signals from the gut, vestibular system, blood chemistry, and emotional state. Common causes include gastric emptying problems (GLP-1 drugs, gastroparesis), pregnancy, motion, migraines, infections, and side effects of medications. Most everyday nausea responds to ginger, slow eating, hydration, and addressing the underlying trigger.

Why we feel nauseous

The brain has a vomiting centre that integrates four input streams: the gut (stretch, irritation, slow emptying), the vestibular system (motion, vertigo), the chemoreceptor trigger zone in the brain (drugs, toxins, blood chemistry), and higher centres (anxiety, smells, sights). When any input reaches threshold, nausea results. This is why nausea has so many causes, many different pathways lead to the same end feeling.

Common causes

  • GLP-1 drugs (Ozempic, Wegovy, Mounjaro): slowed gastric emptying. Peaks in first 4-8 weeks and after each dose increase.
  • Pregnancy (morning sickness): peaks 8-14 weeks, usually fades by 16 weeks.
  • Migraine: nausea is a core migraine symptom, not just an add-on.
  • Motion sickness.
  • Gastroenteritis (viral or bacterial).
  • Anxiety and panic.
  • Side effects of medications: many antibiotics, opioid painkillers, chemotherapy, iron supplements.
  • Vestibular disorders (vertigo, BPPV).
  • Functional dyspepsia.
  • Gastroparesis (slow stomach emptying).

What helps

  1. Ginger: 250-500 mg dried ginger or fresh ginger tea. Best-evidenced over-the-counter remedy. Works for pregnancy nausea, motion sickness, and chemotherapy.
  2. Eat small, frequent meals. Empty stomach makes nausea worse.
  3. Avoid trigger foods (often fatty, fried, spicy, very sweet).
  4. Cold or room-temperature foods are easier than hot, smelly foods.
  5. Sip fluids, don't gulp. Add salt and a small amount of sugar to water for absorption.
  6. Bland carbs (toast, rice, banana, plain crackers) are usually tolerated.
  7. Acupressure wristbands (Sea-Band) help motion sickness and pregnancy nausea.
  8. Vitamin B6 (10-25 mg three times daily) helps pregnancy nausea.
  9. Antihistamines (cyclizine, promethazine) for motion sickness or pregnancy.
  10. Ondansetron for severe nausea, prescription only, used in pregnancy and chemotherapy.

Red flags worth a GP visit

  • Persistent vomiting of food eaten the day before (gastroparesis).
  • Blood in vomit or stools that look black and tarry.
  • Severe abdominal pain.
  • Severe headache or stiff neck (could be meningitis or migraine variant).
  • Loss of consciousness or vision changes.
  • Significant weight loss without other explanation.
  • On a GLP-1 drug with worsening nausea after week 8 (possible severe gastroparesis).

Common questions

Why am I more nauseous on an empty stomach?
Stomach acid sloshes around without food to neutralise it, irritating the stomach lining. Plus blood sugar is lower, which can cause its own nausea. Small frequent meals usually help more than waiting until you feel hungry.
Does ginger really work?
Yes, modestly. Multiple meta-analyses show ginger outperforms placebo for pregnancy nausea, motion sickness and chemotherapy-induced nausea. Effect is real but not dramatic. Best as part of broader management.
Why am I nauseous on Ozempic?
Slowed gastric emptying is the mechanism. Food sits in the stomach longer than usual, stretching the wall and triggering nausea. Peaks in the first 4-8 weeks and after each dose increase. Usually settles within 2 weeks at each dose level.
Can stress cause nausea?
Yes. The brain-gut axis means anxiety triggers gut symptoms including nausea. Many people with chronic nausea have an anxiety component, and treating the anxiety reduces nausea even when the underlying gut function is fine.

Sources