Ambrosia artemisiifolia is a potentially allergenic annual herbaceous plant coming from North America and widespread in Italy, where it can be easily seen since May-April. Its pollination is mainly windborne and each plant is able to produce billions of pollen grains. The pollen peaks are in the hottest days in the absence of rain and wind. In susceptible individuals, the great amount of pollen produced by this species may cause rhinitis and severe asthma attacks. Some allergic subjects can manifest disorders already at a concentration of a few granules per cubic metre. Chemical control is often practiced on a large scale and uses herbicides. A major risk is the result of the unprofessional use of chemicals by the population, especially in residential or very busy areas (eg railways, urban areas). In this paper we propose preventive measures of chemical hazards that may be resulting from the excessive use of plant protection products.