There are no current therapies that specifically target IgE production in human allergic disease. We found that tetracyclines and chemically modified tetracyclines (CMT) that lack antibiotic activity prevent IgE production, making them ideal candidates for anti-allergy therapy. This is based on our findings that minocycline treatment of allergic asthmatic humans significantly improves their asthma symptoms, reduces their oral steroid requirements, and strongly suppresses their ongoing IgE responses. Tetracyclines and CMT also suppress ongoing IgE responses of BPO-KLH sensitized mice in vivo and in vitro and humans IgE responses in vitro. We also found that highly increased levels of phosphorylated p38 MAP kinase, but not phosphorylated JNK or ERK, are expressed by blood T and B cells and monocytes of allergic asthmatic humans. Levels of phosphorylated p38 MAP kinase, but not ERK or JNK, correlated with their IgE. Tetracyclines significantly suppressed expression of phosphorylated p38 MAP kinase by CD4+ and CD8+ T cells but not B cells or monocytes in vivo and in vitro. Our findings open the door to development of new drugs and patents, especially for CMTs that lack antibiotic activity (US 7649113), for treatment of human allergic disease.