While tonsils play an important role in alerting the immune system to pathogens coming into the body through the mouth, there are times when they need to be surgically removed. Doctors have become much more reluctant to carry out tonsillectomies than they were years ago, particularly when it comes to operating on children, as their immune system is still maturing. \"You can talks about a kind of filter. Everything swallowed or breathed in through the mouth passes the tonsils, and pathogens are detected,\" says Werner Hosemann, a German professor specialising in ear, nose and throat (ENT) medicine. The tonsils are covered in deep grooves that increase their surface area and increase the chance of contact between viruses, bacteria and fungi and the immune cells in the tonsils. These then go into action, attacking the pathogens and signalling to the rest of the immune system in a kind of early-warning system. \"In addition, they record them and contribute to the development of the immunological memory — and thus to the body\'s ability to defend itself,\" says Werner Solbach an immunologist at the university clinic in the German city of Luebeck. Nevertheless, tonsils can sometimes be a nuisance, with frequent, or even chronic, tonsillitis the symptom. Then the question poses itself: should they be removed? \"The trend used to be that tonsils were removed too frequently. Today the opposite is the case,\" says Winfried Goertzen of the Bavarian association of ENT specialists. The decisive factor is the fear that removal of the tonsils could weaken the immune system. \"In fact that is only the case when the operation is carried out before the immune system has become established,\" Solbach says. Once the immune system is established — by the age of around six — a tonsillectomy should no longer have an effect on resistance to infection. It is thus a question of age whether the operation should be carried out or not. \"There is greater reluctance to operate on a child. Below the age of four, we try to retain the tonsils because of their role in building up the immune system,\" Goertzen says. \"If someone constantly has infections with discharge, accompanied by fever and pain, then a tonsillectomy is advised,\" Hosemann says. This is because long-running infections overload the immune system and more particularly because of the long-term effects. \"The infection can spread to the throat tissue, causing a peritonsillar abscess,\" he says. This can lead to sepsis in the most extreme cases. Another criterion is the frequency of infection, with more than four to six bouts a year for children and more than three for adults seen as sufficient to indicate a tonsillectomy. The operation is regarded as low-risk, although post-operative bleeding may occur in some cases. For this reason, treatment as an outpatient is not recommended. In addition, certain firm rules have to be followed after the operation. These include avoiding exertion, along with hot or spicy foods. In the event of bleeding lasting more than a few minutes, patients should consult their doctors.