Viruses, like the ones that cause colds, are the most common cause of a sore throat.¹ They spread easily from one person to another. You can pick up a cold virus by breathing in droplets carrying viruses after somebody sneezes.² Antibiotics don't work against viruses.

Some viruses can cause very severe sore throats. For example, mono (mononucleosis), which tends to affect young adults, is usually caused by a virus. Most people recover from mono within four to six weeks without any treatment.

Bacteria can also cause sore throats. You might hear a sore throat called strep throat. This is short for Streptococcus, the most common bacteria to cause a sore throat.¹

You won't usually be able to tell what's caused your sore throat because the symptoms are the same whether it's a bacteria or virus.

Sore throats are often confused with other illnesses that affect parts of the throat. People might say they have bronchitis, tonsillitis, sinusitis, laryngitis (when the voice box gets inflamed), a cold or pharyngitis (the pharynx is that part of the throat between the tonsils and the voice box).