Nausea

Also called sick feeling, queasy.

Dr Chad OkayFounder, Suna Health

3 min read. Updated .

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. Most frequent during dose escalation and after each dose increase, and usually transient.
  • Pregnancy (morning sickness): typically starts around weeks 4-7, peaks around week 9, and resolves by week 20 in most pregnancies.
  • 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: about 1 g per day for at least 4 days. Best-evidenced for pregnancy nausea. Evidence for motion sickness and chemotherapy-induced nausea is mixed.
  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 (pyridoxine) is used for pregnancy nausea in some countries, but UK (RCOG) guidance does not recommend it and the evidence is inconsistent.
  9. Antihistamines (cyclizine, promethazine) for motion sickness or pregnancy.
  10. Ondansetron for severe nausea, prescription only, used in pregnancy and chemotherapy.

When nausea needs more than time

Blood in vomit or black tarry stools is an emergency: 999 in the UK, 911 in the US. Nausea that keeps company with severe tummy pain, a severe headache or stiff neck, fainting or vision changes, repeated vomiting of yesterday's food, or weight going down on its own deserves a doctor promptly rather than patience, and worsening nausea on a GLP-1 medicine after the early weeks is one for your prescriber.

Common questions

Why am I more nauseous on an empty stomach?
Low blood sugar between meals can cause nausea, and hunger signalling can make an empty stomach feel queasy. Small frequent meals usually help more than waiting until you feel hungry.
Does ginger really work?
Yes, modestly. Meta-analyses show ginger outperforms placebo for pregnancy nausea. Evidence for motion sickness and chemotherapy-induced nausea is mixed. 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. It is most frequent during dose escalation and after each dose increase, and is usually transient.
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 addressing it can help reduce symptoms.

Sources

Written by Dr Chad Okay. Contributor: Dr Parisah Hussain, MBChB, BSc (Hons), DRCOG, MRCGP. Last updated 17 September 2026. From Digests.

Digests explains how the body works in general, everyday terms. It is not medical advice. It is not a substitute for someone who can examine you and knows your history, and we do not tell you what dose of any medicine to take.

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