SIDE EFFECTS: Dry lips and mouth, minor swelling of the eyelids or lips, crusty skin, nosebleeds, upset stomach, or thinning of hair may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
Duration of stomach flu depends on the severity of the attack. The condition may become worse in case of infants, young children and elderly who cannot drink sufficient fluids to compensate for dehydration experienced during the illness. For these people, stomach flu can last for 3 weeks or more.
Quick Answer. Symptoms of a stomach bug or flu typically last from one to three days, according to WebMD, though they may last longer in some cases. Healthline indicates that some forms of stomach viruses may show symptoms for up to 10 days. Cramps, diarrhea and vomiting are the most severe symptoms.