The purpose of this article is to review the safety and tolerance of two carbapenems (imipenem/cilastatin and meropenem) in order to establish their possible use in different clinical settings. The tolerance and safety profile of both carbapemens in intravenous and intramuscular formulation is good. With imipenem/cilastatin, nausea and vomiting can constitute a practical problem requiring prolonged times of perfusion and high dilutions. The possibility of administering meropenem in intravenous infusion or bolus injection with lower volumes of fluid, without increasing the incidence of these adverse reactions, may have practical advantages in special situations. The possible neurotoxicity of the imipenem/cilastatin presents limitations of the use in high risk circumstances such as meningitis, previous alterations of CNS, renal insufficiency and concomitant administration of other drugs with neurotoxic profiles and when high doses of administration are needed. The meropenem, by the contrary, can be used in patients with infections of the CNS and other risk factors, at high doses, without increased risk of seizures.