Cashew Nut Shell Oil for Hyposensitization Against Rhus Dermatitis

The requirements for hyposensitizing Rhus-sensitive persons with specific allergens have been given in a previous paper.1The present study demonstrates that cashew nut shell oil may be used for this purpose. This material is cheap, easily obtained, stable, and of fairly constant composition. Cashew Nut Shell Oil The cashew tree (Anacardium occidentale) is extensively cultivated in Brazil and India because of the edibility of its nut; however, the nut does not give up its prize easily, for the kernel is encased in a tough shell. The natives solve this problem by roasting the nuts at high temperatures until the rind becomes brittle; a sharp blow then delivers the kernel. During the heating, a brownish oil capable of causing severe contact dermatitis is released from the rind. The shell contains about 35% of oil by weight. Heating causes the honeycombed oil-secreting cells to burst open. More effi