What system of the human body does nausea and vomiting belong in?

Nausea and vomiting primarily belong to the gastrointestinal system, as they are often responses to disturbances in the digestive tract. Additionally, they can involve the central nervous system, particularly the brain's vomiting center, which integrates signals from various sources such as the stomach, inner ear, and higher brain functions. These symptoms can be triggered by various factors, including infections, motion sickness, and certain medications.