A simplified review of the research carried out in Brazil on tonsils is presented: histopathological findings in children's tonsils with allergy, the detection of Epstein-Barr virus, herpes virus (SV1 e SV2, HHV8) and the correlation between tonsil hypertrophy and recurrence of infection is discussed. The role of allergy in children with tonsillitis and/or tonsil and adenoid hypertrophy are analyzed. After participating in the Tonsils Symposium in 1991, the knowledge of tonsils morphology, immunology and histopathology increased, triggering a change in clinical practice in Brazil. Copyright © 2011 S. Karger AG, Basel.72 136138Endo, L.H., Prigenzi, L.S., Lorand-Metze, I.L., Tonsillectomy: Critical clinical approach based on histological analysis (1989) Folha Med (Brazil), 99, pp. 141-145Endo, L.H., Vassallo, J., Moreira, S.R.L., Allergic tonsillitis: Histopathological study (1992) Adv Otolaryngol, 47, pp. 41-45Endo, L.H., Altemani, A., Chone, C., Idagawa, E., Sakano, E., Histopathological comparison between tonsil and adenoid responses to allergy (1996) Acta Oto-Laryngologica, Supplement, (523), pp. 17-19Endo, L.H., Carvaho, D.S., Sakano, E., Baracat, E.C., Reis, M., Moraes De Oliveira, U., Children palatine tonsils bacteriology: A comprehensive view (1998) Revista Brasileira de Otorrinolaringologia, 64 (6), pp. 553-558Endo, L.H., Ferreira, D., Montenegro, M.C.S., Pinto, G.A., Altemani, A., Bortoleto Jr., A.E., Vassallo, J., Detection of Epstein-Barr virus in tonsillar tissue of children and the relationship with recurrent tonsillitis (2001) International Journal of Pediatric Otorhinolaryngology, 58 (1), pp. 9-15. , DOI 10.1016/S0165-5876(00)00446-8, PII S0165587600004468Endo, L.H., Sakano, E., Camargo, L.A., Ferreira, D.R., Pinto, G.A., Vassallo, J., Detection of Epstein-Barr vírus in children's adenoids by in situ hybridization (2003) Int Congr Ser, 1257, pp. 157-160Endo, L.H., Vassallo, J., Sakano, E., Brousset, P., Detection of Epstein-Barr virus and subsets of lymphoid cells in adenoid tissue of children under 2 years of age (2002) International Journal of Pediatric Otorhinolaryngology, 66 (3), pp. 223-226. , DOI 10.1016/S0165-5876(02)00213-6, PII S0165587602002136Vassallo, J., Azevedo De Camargo, L., Chagas, C.A., Pinto, G.A., Endo, L.H., Search for Herpesvirus 1 and 2 by in situ hybridization in tonsils and adenoids (2005) International Journal of Pediatric Otorhinolaryngology, 69 (3), pp. 345-349. , DOI 10.1016/j.ijporl.2004.10.006Chagas, C.A., Endo, L.H., Sakano, E., Pinto, G.A., Brousset, P., Vassallo, J., Detection of herpesvirus type 8 (HHV8) in children's tonsils and adenoids by immunohistochemistry and in situ hybridization (2006) International Journal of Pediatric Otorhinolaryngology, 70 (1), pp. 65-72. , DOI 10.1016/j.ijporl.2005.04.030, PII S0165587605002636Chagas, C.A., Endo, L.H., Dos-Santos, W.L.C., Pinto, G.A., Sakano, E., Brousset, P., Vassallo, J., Is there a relationship between the detection of human herpesvirus 8 and Epstein-Barr virus in Waldeyer's ring tissues? (2006) International Journal of Pediatric Otorhinolaryngology, 70 (11), pp. 1923-1927. , DOI 10.1016/j.ijporl.2006.06.020, PII S0165587606002266