Ber e 1 is a thermostable albumin 2S protein, a major allergen of Brazil nut (BN). Homology with 2S albumins from other tree and ground nuts is known: Ara h 2 (40 % ), Ara h 6 (48 % ), Ana o 3 (61 % ), Car i 1 (66 % ) and Jug r 1 (68 % ). The sensitization to BN, explored by prick tests, is frequent in patients allergic to other nuts: 19 % . Allergy to NB is rare: 0.48 % of 1047?cases of food allergy recorded in the CICBAA data bank. Severe anaphylaxis to BN represents 0.8 % of cases declared to the Allergy Vigilance Network. The good sensitivity of prick tests and of the determination of specific IgE to BN makes sure the diagnosis of BN allergy when there is a conclusive clinical history, but the lack of specificity does not allow a predicitive value for the diagnosis of allergy when the history is lacking. The new ImmunoCAP? using a recombinant allergen will gain more specificity, discarding the risk of positivity linked to anticarbohydrate IgE. However, the possible cross reactivity between 2S albumins is a non-solved issue that deserves further studies.