AbstractObjectivesTreatment with low-molecular-weight heparins is very common in clinical practice. Exceptionally, some patients develop hepatitis within a few days of starting treatment, and rapid discontinuation of the drug is decisive to avoid chronification.Case presentationThese episodes usually present themselves only with elevated transaminases. We describe the case of a patient who presented a cholestatic pattern, which is very uncommon with this type of drug.ConclusionsHepatitis secondary to heparin therapy is an underdiagnosed entity. The laboratory plays a fundamental role in its diagnosis, given that it initially presents itself without a clear clinical profile.