2. Nausea and vomiting
To diagnose migraines, patients should display at least one episode of nausea with or without vomiting or high sensitivity to sound or light, which will be described in the following paragraph. Nausea and vomiting are gastrointestinal symptoms, but they are associated with the central nervous system because in the brain, there is a control center for the gag reflex that triggers nausea and vomiting under certain circumstances. Pain triggers a series of chemical reactions leading to the activation of such brain centers and the occurrence of nausea with or without vomiting, especially in cases of a headache with high intensity.