Brief Answer:
gastritis would be the main cause that can be treated at home

Detailed Answer:
HI, thanks for using healthcare magic

Abdominal pain and vomiting is most commonly due to infection- usually viral or bacterial infection though other causes may need to be ruled out in some cases
Eg if the pain is in the right lower part of the abdomen , may need to consider appendicitis.
If in the right upper area- gallbladder disease or liver disease

Infections such as urinary tract infections can also cause pain in the lower abdomen and vomiting but there would normally be urinary symptoms- passing urine frequently, discomfort on urination etc

Pain in the lower right or left side may indicate issues with the ovaries or pelvic infection. Severe pain in any area can result in vomiting.

If the pain is in the central upper abdomen then this is likely due to inflammation/irritation of the stomach.This would be gastritis and would be likely due to the viral or bacterial infection mentioned.
This is treated symptomatically- treat symptoms that are present, no treatment of specific virus or bacteria

Treatment of gastritis would involve : (a)holding off all solid food till a 4 hour window with no symptoms
(b)need to replace fluid that she is losing
This has to be done slowly, if excess used, this will provoke vomiting.

Use 1 tsp to 1 tbs every 5 minutes for the first hour, if tolerated (no vomiting at all), then the amount can be increased

Oral rehydration drinks or sport drink such as gatorade should be used.

(c)dramamine or peptobismol to help with the vomiting

(d)if there is any burning- pepcid or zantac can be used

It is difficult to diagnose the exact cause of abdominal pain and vomiting without being able to examine the abdomen so she may need to consider seeing her doctor for assessment.
It is always best to have an examination done especially if the pain is severe.

I hope this helps, feel free to ask any other questions

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