Ambrosia species represent one of the most problematic groups of invasive weeds around the world. The ease they are introduced and spread in new countries, their generalist ecological requirements and functional traits facilitate their invasion and subsequent naturalization in new areas. All of these aspects contribute to increasing their global social and economic impact, which is mostly related to pollen allergy. Here we analyse available scientific publications about Ambrosia artemisiifolia, A. psilostachya, A. tenuifolia and A. trifida, with the aim of defining the current level of knowledge and summarizing important data that is currently scattered throughout the literature. Specifically, we analysed the following: (1) their current global distribution and current stage of invasion; (2) traits and requirements promoting their introduction, reproductive success and adaptation to climate and environment in the non-native range; as well as (3) current knowledge about allergens and elements increasing their impact.