The Food and Drug Administration has accelerated the approval of therapeutically novel drugs so that patients have faster access to innovative drug therapies. Little research, however, has examined the variation in risks among therapeutically novel and less novel drugs. Do drugs that represent greater novelty also entail greater risks for patients? This paper uses post-marketing drug safety surveillance data from the FDA to examine the adverse drug reactions (ADRs) associated with novel and less novel drugs. Negative binomial regressions are used to examine the impact of a drug's FDA novelty rating on its ADR count controlling for differences in drug utilization, the conditions being treated, disease characteristics, patient characteristics, drug review times, and year-specific effects. Results show that drugs deemed novel by the FDA are associated with a greater number of serious drug reactions, including those that result in hospitalization and death, than less novel drugs. These results suggest that novel drugs pose greater risk of serious ADRs for patients relative to less novel drugs.