The basophil degranulation test (BDT) after Shelley has been simplified and tried on patients allergic to house-dust or to house-dust mites. All 20 patients reacted to the mite extracts and 19 out of 20 to the house dust extracts. Out of 20 control persons 17 had negative results to the mite extract and 16 to the house-dust extract. The advantages of this new simplified method are discussed.