Nausea, headache, and loss of appetite are associated with gastrointestinal colds, hypertension, and occupational brain disease. In the case of gastrointestinal flu, the patient may experience symptoms in both the digestive and respiratory systems. The digestive system is characterized by nausea, vomiting, bloating, diarrhea, loss of appetite, etc. And because the virus invades the respiratory system, patients may suffer from poor breathing, nasal congestion, runny nose, etc. Some people may also suffer from head pain due to lack of oxygen to the brain. Hypertension is common in middle-aged and elderly people. The condition affects the brain tissue during an attack and even leads to plant nerve disorders, so patients may experience nausea, headache, and loss of appetite. If there is an occupational disease in the skull, such as brain tumor, it will not only damage the brain tissue, but also stimulate the central nerve of vomiting, so the patient will have nausea and loss of appetite along with headache.