Tonsillitis is an infection or inflammation of the tonsils which is usually caused by a bacteria or virus. Sometimes streptococcus pyogenes,"Strep", is the bacterial cause of tonsillitis. Adenovirus and "Mononucleosis" (Epstein Barr) are two common viral causes.
If you have tonsillitis, please see your doctor to make sure you do not have a bacterial cause and need antibiotics. If the infection is Strep, antibiotics are needed to protect from scarlet fever and rheumatic heart disease. If the infection is viral, antibiotics will not help and your body will fight the virus. Either way, make sure you get rest and good nutrition.