BACKGROUND: Increasing numbers of research have revealed an etiological association between peripheral blood markers and allergy. Nevertheless, whether these associations are causal and whether they vary among different allergic diseases and ethnicities remain unclear. METHODS: 32 peripheral biomarkers with consistent definition were collected from three nationwide biobanks (UK Biobank, FinnGen, and BioBank Japan). Summary-level data for asthma (n=774,328), dermatitis (n=880,733), and allergic rhinitis (n=893,300) were obtained from these biobanks. Mendelian randomization (MR) analyses and meta-analyses were applied to explore the generalizability and heterogeneity of causal effects among different allergic diseases and ethnicities. The clinical data (n=9,877) in China and US were collected to verify peripheral markers affecting allergy. RESULTS: ONCLUSIONS: Our results support the causal effects of 22 blood heritable factors on allergic diseases, providing novel insights into the comprehensive assessment of allergic risks and the design of universal and personalized interventions.