Abstract  e term weed is referring to plants used as culinary
herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pol-len of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen aller-gies. Presently, 35 weed pollen allergens have been identi ed.  e most relevant belong to the protein families of pectate lyases, defensin-like proteins, non-speci c lipid transfer proteins, and Ole e 1-like proteins.  e sensitization frequency depends on geographic regions and might a ect more than 50 % of pollen allergic patients in distinct regions. Due to overlapping  owering seasons, similar habitats, polysensitizations and cross-reactive (pan)- allergens, it is di cult to diagnose genuine weed pollen sen-sitization using pollen extracts. Marker allergens for component-resolved diagnostics are available for the important weed pollen.  ese are Amb a 1 (rag weed), Art v 1 (mugwort), Pla l 1 (English plantain) and Par j 2 (pellitory). Molecule-based approaches can be used to identify the primary sensitizer and thus enable selection of the appropriate weed pollen extracts for allergen immunotherapy.