Since the introduction of the interferons in the 1990s, a multitude of different immunomodulatory and immunosuppressant disease-modifying therapies for multiple sclerosis (MS) have been developed. They have all shown positive effects on clinical endpoints such as relapse rate and disease progression and are a heterogeneous group of therapeutics comprising recombinant pegylated and non-pegylated interferon-β variants, peptide combinations, monoclonal antibodies, and small molecules. However, they have relevant side effect profiles, which necessitate thorough monitoring and straightforward patient education. In individual cases, side effects can be severe and potentially life-threatening, which is why knowledge about (neurological and non-neurological) adverse drug reactions is essential for prescribing neurologists as well as general practitioners. This paper aims to provide an overview of currently available MS therapies, their modes of action and safety profiles, and the necessary therapy monitoring.