Updated 7th of March 2021

Tonsils are a group of lymphatic organs located in a person’s throat that play an essential role in fighting infections as they constitute the immune system’s first line of defence in the pharynx (back of the throat). Some tonsils are partially visible when looking deep in the mouth. There are four groups: the adenoid (or pharyngeal tonsil), the tubal tonsils, the palatine tonsils, and the lingual tonsil. All tonsils collectively form a circle arrangement called the Waldeyer’s ring.

Even if the main function of tonsils is defending the body from harmful organisms, their removal does not make a person more susceptible to infections.

Types of tonsils

4 types of tonsils, pharyngeal, tubular, palatal, lingualThere are four types of tonsils located in the oropharynx and nasopharynx, which are parts of the throat found behind the mouth (oro-), or in the nasal cavity (naso-).

Type Number Location
Pharyngeal tonsil (also called Adenoid) 1 Roof of nasopharynx (the superior part of the pharynx).
Tubal tonsils 2 Opening of the Eustachian tube (tube that links the nasopharynx to the middle ear).
Palatine tonsils 2 Left and right sides at the back of the throat, but more precisely between the palatoglossal and the palatopharyngeal arches.
Lingual tonsil 1 The most back part of the tongue, more precisely behind the terminal sulcus of the tongue.

The palatine tonsils grow until puberty, and then gradually shrink the following years.

The adenoid tonsil reaches its largest size at the age of 5, starts to become smaller at the age of 7, and its size becomes minimized at adulthood.


The tonsils are immunocompetent organs, which means that they are part of the body’s immune system and able to defend it when there is exposure to an antigen or pathogen (viruses or bacteria that can produce disease). Because of their location at the throat and palate, they can stop germs entering the body through the mouth or the nose.

If there is an infection, tonsils can grow in size because blood flow is increased towards them. This may happen in any type of infection, including a common cold.

Tonsils have, what we call, M cells on their surface that can recognize germs. These cells alert white blood cells (lymphocytes), called B cells and T cells, which are then responsible for killing those germs.

Conditions and diseases

Acute tonsillitis is when bacteria or viruses infect the tonsils, causing inflammation and swelling. This condition can be presented with fever, loss of voice, difficulty swallowing, and a white or yellow coating visible when looking in the mouth. Treatments consist of pain killers, and antibiotics if bacteria is involved.

Chronic tonsillitis is a condition when infection of the tonsils is persistent. If the problem is recurrent (about 4-7 times per year), persistent and where tonsils are enlarged, surgical removal is recommended (tonsillectomy).

Peritonsillar abscess is an infection of the tonsils where a substantial amount of pus is found. This is a condition where the abscesses must be drained urgently to prevent breathing obstruction or systemic sepsis (infection of the whole body).

Acute mononucleosis, which is known to be caused by the Epstein-Barr virus, leads to swelling of the tonsils, fever, sore throat, rash, and fatigue.

Strep throat, also called streptococcal pharyngitis, is a bacterial infection of the tonsils and throat caused by group A streptococcus. Symptoms are sore throat, fever and neck pain.

Hypertrophic tonsils are enlarged tonsils that reduce the size of the airway. This situation can lead to snoring or sleep apnea. Surgical removal is therefore sometimes recommended.

Tonsilloliths are tonsil stones, which are formed when trapped debris hardens, or calcifies inside the tonsils. Treatment depends on how bad tonsil stones are, and ranges from no treatment at all, to curettage, removal by laser, to tonsillectomy.


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The information above should be used as a reference only. Any medical decision should not be taken before consulting a health care professional.