Nausea with flu: what to know and do

Flu may upset the stomach as your immune system responds to the infection. Fever, mucus swallowed from a cough, pain, medicines taken on an empty stomach and not drinking enough can all add to the sick feeling. Some people also have vomiting or diarrhoea, although these symptoms are not present in everyone with flu.

Nausea itself does not confirm flu. Other illnesses, including Food Poisoning or Gastroenteritis, can cause a similar combination of stomach symptoms. Consider the whole pattern: sudden fever, chills, cough, sore throat, body aches and tiredness support a respiratory infection, while prominent diarrhoea or stomach cramps may point elsewhere.

Take small, frequent sips of water or an oral rehydration drink. If drinking feels difficult, try cool fluids or ice chips. Eat modest portions of plain foods such as toast, rice, soup or bananas when you feel able, and avoid alcohol, very rich meals and strong smells that trigger nausea.

Rest and follow the label or a clinician’s advice for any flu treatment. Check before combining medicines, because some products contain the same pain-relieving ingredient. Keep track of urination, alertness and whether fluids stay down; these clues help show whether dehydration is developing.

Seek urgent help for trouble breathing, chest pain, new confusion, fainting, severe weakness, blue or grey lips, a stiff neck, or a severe headache. Get prompt medical advice if you cannot keep fluids down, pass very little urine, feel increasingly drowsy, or have worsening abdominal pain.

Contact a clinician if nausea is not easing as the flu symptoms improve, if a fever returns after improving, or if you have pregnancy, an immune condition, or a long-term illness that raises your risk from infection.

Could another illness explain my nausea, and which symptoms would make testing useful? Are my medicines or an empty stomach aggravating it? What is the safest way for me to manage fluids and fever?