Pregnancy may variously modify the natural history of allergic disorders through occurring endocrinologic, functional and immunological changes. A pharmacologic treatment of allergic diseases (mainly asthma) is often necessary during pregnancy. On the other hand, a drug should be not potentially teratogenic and should not have serious side effects, both for the mother and the fetus. This paper reviews current knowledge about allergic diseases during pregnancy, considering the points of view of the different specialists involved in their management. Topical mucosal agents seem to be the safest, due to their minimal or absent absorption which should reflect reduced side effects. Preferred agents should be topical antihistamines (for rhinitis and conjunctivitis), and cromones and topical steroids (for asthma), as they are both safe and effective.