Nausea and vomiting can be associated with other symptoms of the underlying medical conditions such as diarrhea, abdominal pain, dizziness and headache.

You should seek a vomiting specialist’s help when your symptoms persist more than a week and the cause of the symptoms is not obvious. 

You should also seek medical help if you have the following vomiting symptoms

1. Dehydration and can’t keep the food down 
2. Severe abdominal pain
3. Lethargy and confusion
4. Blood in the vomit (“coffee grounds” appearance)
5. High fever

Many things can bring on nausea and vomiting. Some of the common causes of vomiting are:

1. Food poisoning and gastroenteritis: It refers to infection of the gut by a bacterial or a virus that causes abdominal pain, vomiting, fever and diarrhoea. 
2. Medications: There are many medications that can cause nausea and vomiting. Chemotherapy,for instance, is well known to be able to cause nausea and vomiting. 
3. Alcohol: If you drink too much alcohol, you will vomit.
4. Pregnancy especially in the first trimester
5. Body reaction to something disgusting and distressing, stress and even to severe pain.
6. Motion sickness

Nausea and vomiting can be a sign of a more serious illness. Some examples of serious conditions that your vomiting doctor might look out for include:

1. Brain conditions such as migraine, brain infection, a brain tumour. It is usually accompanied by a headache
2. Ear disorder which can cause giddiness, vertigo, hearing impairment and vomiting
3. Gastrointestinal disorder such as obstruction of the digestive tract which can cause vomiting after every meal. A common cause of obstruction is cancer. Gastroparesis, a condition where the movement of the stomach is impaired, would also cause vomiting. 
4. Severe chronic medical conditions such as heart failure, kidney failure and cancer

The work-up for the cause of vomiting depends on the possible causes after the assessment. Some of the more common investigations  that vomiting specialists might administer are gastroscopy, barium study, barium meal and CT scan of the abdomen and MRI of the brain.

There are several vomiting treatments:

• Drink adequate amount of water to prevent dehydration
• Take simple and light food such as soft diet until the vomiting episode has passed
• avoid spicy or oily food
• Eat smaller but more frequent meals.
• Avoid activity after eating.
• Discontinue medications which can irritate the stomach.

If vomiting and diarrhea do not improve with the home measures, your vomiting doctor may use oral rehydrating solution to help the hydration and anti-vomiting medication to control the vomiting.