The most common causes of a sore throat and upset stomach include the common cold, sinusitis, and a bacterial infection known as strep throat. In rare cases, these symptoms can also indicate an influenza infection, also known simply as the flu. These symptoms alone are not usually signs of serious illness. However, when combined with other symptoms, such as an unusually high fever, confusion, vomiting, diarrhea, or loss of consciousness, a more serious illness could be the cause.
The rhinovirus, also known as the common cold, sometimes causes a sore throat and an upset stomach. Other symptoms may also include sneezing, nasal congestion, fever, cough, hoarse voice, and chills. Most people experience the common cold at least once in their life, and many experience multiple episodes with this illness.
People with a sinus infection, also known as sinusitis, will often experience a sore throat, and swallowing mucus can cause an upset stomach. A headache can also accompany these symptoms, as sinus swelling often leads to pain in the forehead, face, and ears. Other symptoms of sinusitis include a runny nose, nasal congestion, cough, fever, and thick mucus production. Symptoms may also be worse at night when lying down.
Strep throat can also cause a sore throat and upset stomach. Such may be the case particularly in adults with heart problems or children under the age of 16, as both groups are more susceptible to the disease than the rest of the population. This illness is often confused with the common cold as it is also accompanied by symptoms such as fever, chills, and headache, but includes symptoms such as skin rash, loss of appetite, and stomach pain. A sore throat that is accompanied by congestion is probably not strep throat, but may simply be a common cold. However, to accurately distinguish symptoms, a throat culture should be examined by a healthcare professional.
Occasionally, a sore throat and upset stomach can be symptoms of the flu. Although influenza is a respiratory infection, upset stomach, diarrhea, and vomiting can accompany the usual symptoms of cough, muscle aches, headache, and congestion. There are also many different types of influenza, such as the H1N1 virus, bird flu, and others. While most are treatable with rest and antiviral medications, persistent symptoms, including vomiting or diarrhea, sometimes require emergency treatment.