Can you eat before having a chest CT scan. Chest CT plain scan is a method of examining chest diseases using CT, and there is no need to prohibit eating and drinking before the examination, as eating does not affect the results of the examination and diagnosis. However, if chest lesions are found during the chest CT scan and further enhanced CT examination is needed, fasting is required. This is because injection of contrast medium may cause adverse reactions, especially nausea and vomiting due to allergic reactions, and eating will aggravate nausea, vomiting, gastrointestinal food reflux, and risk of respiratory tract obstruction. It is recommended to consult your doctor before having a chest CT scan, make relevant preparations for the examination, and cooperate with your doctor in time to receive treatment or further examination if abnormalities are found during the examination.