What is wrong if you feel constipated and took laxative which helped but then last night tonight vomited only phlegm saliva my stomach feels empty even after eating?

Reasons for feeling constipated and then experiencing vomiting of phlegm and saliva with an empty stomach despite eating:

1. Medication Side Effects: Some laxatives can cause side effects such as nausea and vomiting. If you're taking a laxative, check the medication guide for a list of potential side effects.

2. Gastrointestinal Issues: Vomiting phlegm and saliva, along with an empty feeling in the stomach, may indicate an underlying gastrointestinal issue, such as an infection or inflammation.

3. Dehydration: Vomiting and diarrhea can lead to dehydration, which can cause an empty feeling in the stomach and constipation.

4. Dietary Factors: Eating certain foods or consuming excessive amounts of certain substances, such as caffeine or alcohol, can contribute to constipation and vomiting.

5. Stress or Anxiety: Stress and anxiety can impact the digestive system and cause symptoms such as constipation and vomiting.

6. Medical Conditions: Some medical conditions, including certain neurological disorders and hormonal imbalances, can lead to constipation and vomiting.

If your symptoms persist or worsen, or if you have concerns about your health, it's essential to consult a healthcare professional for proper evaluation and treatment.