Unexplained Nausea

What Causes Unexplained Nausea?

Unexplained nausea can have various causes, ranging in severity from 'minor' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose unexplained nausea, we could:
  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "unexplained nausea" as a symptom.  Here are eight of many possibilities (more below):
  • Giardia
  • Diabetes II
  • Food Poisoning
  • Intestinal Obstruction
  • Aspartame/Neotame Side-Effects
  • Non-Hodgkin's Lymphoma
  • Sarcoidosis
  • Stomach Cancer

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
omnivorous diet
significant abdominal pain
shortness of breath when at rest
constant thirst
very irregular menstrual cycles
severe flatulence
vomiting for 1-3 months
stomach cancer
difficulty losing weight
nasal congestion
severe calorie restriction
type 2 diabetes IDD
... and more than 100 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of unexplained nausea:
Cause Probability Status
Sarcoidosis 92% Confirm
Food Poisoning 19% Unlikely
Giardia 30% Unlikely
Stomach Cancer 5% Ruled out
Non-Hodgkin's Lymphoma 4% Ruled out
Diabetes II 4% Ruled out
Aspartame/Neotame Side-Effects 2% Ruled out
Intestinal Obstruction 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

In the Gastro-Intestinal Symptoms section of the questionnaire, The Analyst™ will ask the following question about unexplained nausea:
Approximately how often do you suffer from unexplained nausea? Do not include nausea that has an obvious cause, for example pregnancy, hunger or motion sickness.
Possible responses:
→ Don't know
→ Never / very rarely
→ Occasionally - a few times per year
→ Regularly - a few times per month
→ Often - several times per week
Based on your response to this question, which may indicate no unexplained nausea, occasional unexplained nausea, regular unexplained nausea or frequent unexplained nausea, The Analyst™ will consider possibilities such as:
Congestive Heart Failure

Accumulation of fluid (due to congestive heart failure) in the liver and intestines may cause nausea, abdominal pain, and decreased appetite.

Enlarged Spleen

Enlarged Spleen also suggests the following possibilities:


Hypersplenism is sometimes referred to as enlarged spleen (splenomegaly), but in fact an enlarged spleen is one of the symptoms of hypersplenism.  What differentiates hypersplenism is its premature destruction of blood cells.

Infectious Mononucleosis - Mono

About 50-75% of people with mononucleosis have some spleen enlargement, usually seen two to three weeks after they first become sick.  Whether or not the spleen is enlarged, people who have mono should not lift heavy objects or exercise vigorously – especially participating in contact sports – for two months after they get sick, because these activities increase the risk of rupturing the spleen, which can be life-threatening.  If you have mono and get a severe sharp, sudden pain on the left side of your upper abdomen, go to an emergency room immediately.


ALL, CML, or hairy cell leukemia can cause enlargement of the spleen.

Fluoride Toxicity

Nausea is an early sign of fluoride toxicity.


Acute gastroenteritis is a common cause of acute care-seeking and is second only to the common cold as a cause of lost work time.  Bacterial, viral, and parasitic pathogens cause this illness which is characterized by diarrhea and/or vomiting.  Vomiting is especially common with infections caused by rotaviruses, enteric adenovirus, Norwalk agent, and calicivirus.


In more severe cases there may be loss of appetite, nausea, vomiting, constipation, confusion or impaired thinking and memory, and increased thirst and urination.

Zinc Toxicity

Symptoms of zinc toxicity include nausea, vomiting and fever.