Cladribine is a prodrug, a synthetic analogue of deoxyadenosine, approved for use as selective immune reconstitution therapy in very active recurring multiple sclerosis in adults.To review the development of the drug, its mechanism of action and the efficacy and safety data obtained to date, as well as to establish recommendations of Spanish experts for its use in clinical practice.The treatment of multiple sclerosis has been simplified with cladribine tablets, and two short courses of administration for two consecutive years (maximum 20 days) are needed to maintain an efficacy of up to four years after the first dose. Results of clinical trials have demonstrated the safety, tolerability and long-term efficacy of cladribine tablets in patients with recurring multiple sclerosis. Thus, patients treated with cladribine presented a significant reduction in the rate of flare-ups, in the risk of disability progression and in the development of new lesions in magnetic resonance imaging compared to those treated with placebo. In terms of safety, the treated patients had a higher frequency of lymphopenia, in relation to its mechanism of action, and of infections by herpes zoster virus. Long-term results with eight years' follow-up have shown that treated patients are not at greater risk of developing serious events, such as malignant neoplasms or opportunistic infections.Cladribine is the first short-course oral therapy that has been shown to be effective and safe in patients with very active recurring multiple sclerosis, and with a sustained effect over time. The recommendations of Spanish experts on its usage are a fundamental complement to the considerations described by the regulatory agencies.