Persistent nausea that lasts days or weeks usually points to one of a handful of common causes: a digestive issue, a medication side effect, stress, pregnancy, or a food your body isn’t tolerating well. The challenge is that nausea is one of the least specific symptoms in medicine, connected to dozens of conditions across nearly every body system. That vagueness is exactly why it’s so frustrating when it won’t go away. Here’s how to narrow it down.
Digestive Problems Are the Most Common Culprit
If your nausea tends to show up after eating, gets worse when you lie down, or comes with bloating, heartburn, or stomach pain, a gastrointestinal issue is the most likely explanation. Gastroesophageal reflux disease (GERD) is one of the top causes of ongoing nausea in adults. Stomach acid backs up into your esophagus, and while most people associate reflux with heartburn, nausea can be the main symptom for some people, especially if the reflux happens at night or after large meals.
Gastroparesis is another possibility, particularly if you feel full very quickly or notice that food seems to sit in your stomach for hours. In this condition, the muscles of the stomach wall don’t contract properly, so digestion slows to a crawl. The result is nausea, bloating, and sometimes vomiting of food you ate much earlier. Gastroparesis is more common in people with diabetes but can happen without any clear cause. Interestingly, Johns Hopkins researchers have found that some patients with completely normal stomach-emptying tests still show the same underlying cellular damage seen in gastroparesis, which means the line between “slow stomach” and “functional digestive problems” is blurrier than most people realize.
Peptic ulcers, irritable bowel syndrome, and even simple chronic gastritis (inflammation of the stomach lining) can all produce nausea that comes and goes for weeks. A pattern tied to meals, especially fatty or spicy ones, is the biggest clue that your gut is the source.
Medications You Already Take
This is one of the most overlooked causes. Nausea is a side effect of a surprisingly large number of common medications, affecting 20 to 50% of people taking certain drugs. Antidepressants in the SSRI class (like fluoxetine or sertraline) are well-known offenders, especially in the first few weeks. Pain relievers, including over-the-counter options like ibuprofen and aspirin, irritate the stomach lining and can cause nausea even at normal doses. Oral contraceptives, antibiotics, and opioid painkillers are also frequent triggers.
If your nausea started around the same time you began a new medication or changed your dose, that’s a strong signal. With opioid painkillers specifically, nausea occurs in up to 70% of patients during initial use and persists in 10 to 40% of people who take them long-term. Even supplements like iron or certain vitamins can be the culprit. Check the timing before assuming something else is wrong.
Stress, Anxiety, and the Gut-Brain Connection
Your brain and your digestive system are in constant communication, and stress can hijack that connection in a very physical way. When you’re anxious or under chronic stress, your body releases a cascade of hormones, including cortisol and a hormone that regulates water balance. These hormones directly affect how your stomach and intestines move and contract. Research using continuous blood sampling has shown that stress hormone levels spike in direct proportion to how severe nausea becomes, with worse nausea triggering a bigger hormonal response, which in turn makes the nausea worse.
Stress-related nausea often comes without any other digestive symptoms. You may not have diarrhea, bloating, or heartburn. It can feel like a low-grade queasiness that sits in the background all day, getting worse during high-pressure moments or when you haven’t slept well. If you’ve been going through a difficult period at work, in a relationship, or with your mental health in general, this is worth considering seriously. It’s not “just in your head.” The hormonal changes are measurable and real.
Pregnancy and Hormonal Shifts
If pregnancy is a possibility for you, it’s one of the first things to rule out. Nausea from pregnancy typically starts around six weeks after your last period, with most women noticing it before nine weeks. It peaks between weeks eight and ten and, despite the name “morning sickness,” can happen at any time of day. Some women describe it as motion sickness, others as a constant feeling of something stuck in their throat, and others as intense hunger pangs that eating doesn’t fix.
In about 3% of pregnancies, nausea becomes severe enough to qualify as hyperemesis gravidarum, which involves vomiting more than three times a day, losing 10 or more pounds, and becoming dehydrated. Signs of dehydration include dark urine, dizziness when standing, and producing very little urine. Even milder pregnancy nausea can be debilitating enough to disrupt daily life. A home pregnancy test is the fastest way to check this off the list.
Food Intolerances You Haven’t Identified
A food intolerance is different from an allergy. It won’t cause hives or a swollen throat, but it can produce chronic, low-grade nausea that’s hard to pin down because the reaction is often delayed by hours. Lactose intolerance is the most common type, affecting people who can’t fully digest the sugar in milk and dairy. But you can develop an intolerance to almost anything: gluten (found in bread, pasta, and baked goods), histamine (found in aged cheese, wine, and cured meats), caffeine, alcohol, sulfites in beer and cider, or even salicylates found naturally in certain fruits and vegetables.
The tricky part is that food intolerances can develop at any age, even to things you’ve eaten your whole life without problems. If your nausea is inconsistent, showing up on some days but not others, keeping a food diary for two weeks can reveal patterns you’d never notice otherwise. Pay special attention to dairy, wheat, and anything fermented or aged.
Inner Ear and Balance Problems
Your inner ear plays a central role in balance, and when something goes wrong there, nausea is one of the first symptoms. Benign paroxysmal positional vertigo (BPPV) happens when tiny calcium crystals inside the ear shift out of place and drift into the wrong canal. This causes brief but intense episodes of dizziness and nausea, typically triggered by rolling over in bed, looking up, or tilting your head. Labyrinthitis, an inflammation of the inner ear usually caused by a viral infection, produces nausea that can last days or weeks alongside a persistent sense that the room is spinning or tilting.
The key clue for an inner ear problem is that the nausea comes with dizziness or a feeling of being off-balance. If you feel fine when you’re sitting still but queasy when you move your head, this is worth exploring.
Environmental Causes to Rule Out
Low-level carbon monoxide exposure is an underrecognized cause of persistent nausea. The symptoms, which include headache, dizziness, weakness, upset stomach, and confusion, mimic the flu so closely that many people don’t suspect their home environment. If your nausea improves when you leave your house and returns when you come home, or if other people in the household feel similarly unwell, get your home tested. CO is odorless and colorless. A detector costs less than $30 and can prevent a life-threatening situation.
Simple Relief That Actually Helps
While you work on finding the root cause, ginger is one of the best-studied natural remedies for nausea. Clinical trials have found that 250 mg to 1 gram per day, divided into three or four doses, is effective for multiple types of nausea. Higher doses (up to 2 grams) don’t appear to work any better than 1 gram. You can get this through ginger capsules, ginger tea made from fresh root, or even ginger chews.
Eating smaller, more frequent meals reduces the workload on your stomach. Cold or room-temperature foods tend to be better tolerated than hot ones, because they produce less smell. Staying hydrated matters more than eating if you’re struggling to keep food down. Small sips of water, clear broth, or an electrolyte drink throughout the day are more effective than trying to drink a full glass at once.
Red Flags That Need Immediate Attention
Most causes of ongoing nausea aren’t dangerous, but certain combinations of symptoms require urgent medical evaluation. Get to an emergency room if your nausea comes with chest pain, severe abdominal cramping, confusion, blurred vision, a high fever with a stiff neck, or rectal bleeding. Vomit that contains blood, looks like coffee grounds, or is bright green also warrants immediate care.
Signs of dehydration, including dark urine, dizziness when you stand up, dry mouth, and urinating much less than usual, mean you need medical fluids and shouldn’t wait it out at home. The same applies if you’re experiencing the worst headache of your life alongside the nausea, especially if it’s a type of headache you’ve never had before.