Monitoring of allergic inflammation includes direct examination of biopsy specimens from mucosa and epithelium, and indirect study by sputum, bronchoalveolar and nasal lavage fluid and peripheral blood. Although, some of these detection assays are not applicable to clinical use, it is now possible to measure a number of inflammatory mediators released from cells participating in allergic disease. The release of performed histamine from peripheral blood basophils challenged with specific antigen remains a valuable in vitro correlate of immediate hypersensitivity reactions. However, other mediators such as LTC4 and IL-4 are also generated by basophils upon IgE dependent activation. Tryptase and PGD2 are released from mast cells upon activation. Eosinophils contain in their granules proteins that cause damage to the bronchial epithelium: MBP and ECP. It is possible to measure soluble markers from other cells (T cells, macrophages, platelets, endothelial cells) involved in allergic inflammation. Detection of mediators have produced data that have significantly added to our understanding of the mechanisms and allowed better pharmacological control of allergic inflammation.