Nausea is a very common symptom and can come from many different causes, ranging from mild and temporary to more serious medical issues.

Very common everyday causes

These are frequent, usually short‑term reasons people feel nauseous:

  • Stomach bug or food poisoning : Sudden nausea with vomiting, diarrhea, stomach cramps, sometimes fever, often starting within hours of eating contaminated food or after contact with someone sick.
  • Motion sickness: Nausea triggered by car, bus, boat, or plane travel, often with dizziness and cold sweats.
  • Overeating, rich or spicy food, or alcohol: Heavy meals, greasy food, or drinking too much can irritate the stomach and cause nausea or vomiting.
  • Stress and anxiety: Strong stress, panic, or intense emotions can cause a “knot” in the stomach, nausea, and sometimes diarrhea.
  • Strong smells: Perfume, smoke, fuel, or cooking smells can trigger nausea in some people.

Example

Someone eats street food and 4–6 hours later develops nausea, stomach cramps, and diarrhea; this pattern is typical of food poisoning.

Medical conditions that often cause nausea

Sometimes nausea is a symptom of an underlying condition:

  • Viral “stomach flu” (gastroenteritis): Nausea, vomiting, watery diarrhea, cramps, and low‑grade fever, often spreading through families or schools.
  • Acid reflux or GERD: Burning in the chest, sour taste in the mouth, nausea after meals or when lying down.
  • Gastritis or ulcers: Dull or burning upper‑stomach pain, worse with an empty stomach or certain foods, plus nausea.
  • Gallbladder problems (like gallstones): Nausea with upper‑right or middle‑upper abdominal pain, often after fatty foods.
  • Pancreatitis: Severe upper abdominal pain that can go through to the back, nausea, and vomiting.
  • Migraine: Throbbing headache, sensitivity to light and sound, and significant nausea or vomiting.
  • Inner ear / balance issues: Vertigo (room spinning), difficulty walking straight, and nausea or vomiting.

Situations specific to certain people

Some causes depend on your life situation or medications:

  • Pregnancy (especially early): Nausea is extremely common in the first trimester, sometimes with or without vomiting, often worse in the morning or with certain smells.
  • Medicines: Many drugs (painkillers like opioids, some antibiotics, antidepressants, chemotherapy, etc.) list nausea as a side effect.
  • Alcohol or drug use: Drinking heavily or using certain substances can trigger acute nausea or vomiting.
  • Chronic conditions: Diabetes (gastroparesis), inflammatory bowel disease, severe kidney or liver disease, and others can include persistent nausea.
  • Cannabis overuse: Frequent heavy use can, in some people, cause repeated episodes of nausea and vomiting (cannabinoid hyperemesis syndrome).

Red‑flag signs: when nausea can be serious

Nausea alone is often not dangerous, but certain symptoms alongside it mean you need urgent medical attention:

  • Chest pain, pressure, or pain spreading to arm, jaw, or back.
  • Sudden, severe headache with neck stiffness, confusion, difficulty speaking, or weakness.
  • Vomit that is bright red, looks like coffee grounds, or black/tarry stools.
  • Severe abdominal pain, a hard or swollen belly, inability to pass gas or stool.
  • High fever, stiff neck, confusion, or rash.
  • Signs of dehydration: very dry mouth, dark urine or not peeing, dizziness, feeling faint when standing.
  • Persistent vomiting (cannot keep fluids down for more than 12–24 hours, or sooner in children or frail adults).

If any of these apply to you, you should seek emergency or same‑day medical care immediately.

Things you can try at home (if symptoms are mild)

For mild, short‑term nausea without red flags, these self‑care steps often help:

  • Take small sips of clear fluids (water, oral rehydration solution, weak tea) regularly.
  • Eat bland foods in small amounts—crackers, toast, plain rice, bananas—once you can tolerate solids.
  • Avoid greasy, spicy, or very sweet foods, alcohol, and caffeine until you feel better.
  • Get fresh air, sit upright, and avoid lying flat right after eating.
  • Rest, reduce screen time, and avoid strong smells.
  • Ginger (tea, lozenges) or peppermint may help some people.

Over‑the‑counter anti‑nausea medications may help but can interact with other drugs or mask serious problems, so they are best used with a professional’s guidance.

Why “why am I nauseous?” is hard to answer online

Nausea is a non‑specific symptom that can range from something simple like motion sickness or a mild virus to more serious illnesses, and the true cause depends on details like:

  • How long you’ve been nauseous
  • Whether you are pregnant, on medications, or have chronic illnesses
  • What other symptoms you have (pain, fever, diarrhea, headache, chest pain, etc.)
  • Recent travel, new foods, injuries, or infections

Because of that, any online explanation is only a general guide, not a diagnosis, and it should not replace seeing a doctor in person.

If you tell me how long you’ve been feeling this way, what other symptoms you have, and any relevant things like pregnancy, medications, or recent food changes, I can help narrow down the most likely categories and what to do next (still not a substitute for real medical care). Information gathered from public forums or data available on the internet and portrayed here.