why do we vomit

Motion sickness or seasickness
Early stages of pregnancy (nausea occurs in approximately 50%-90% of all pregnancies; vomiting in 25%-55%)
Medication-induced vomiting
Intense pain
Emotional stress (such as fear)

Gallbladder disease
Food poisoning
Infections (such as the “stomach flu”)
A reaction to certain smells or odors
Heart attack
Concussion or brain injury
Brain tumor
Some forms of cancer
Bulimia or other psychological illnesses
Gastroparesis or slow stomach emptying (a condition that can be seen in people with diabetes)
Ingestion of toxins or excessive amounts of alcohol