Inclusion Criteria:  Age > 18 years fever (axillary temperature >37.5º C) or history of fever during the prior 48 hours in absence of another obvious cause (such as pneumonia, otitis media) a non-mixed P. falciparum infection with 250 and 100,000 asexual parasites/µl to be determined by a thick film or thick film and blood smear microscopic test  Exclusion Criteria:  Not being able to drink vomiting (more than twice within the prior 24 hours) recent history of seizures (1 or more in the previous 24 hours) alteration of the consciousness level not being able to seat or stand up, signs of serious malaria (World Health Organization criteria) other chronic or severe diseases (i.e., cardiac, renal and hepatic diseases, HIV/AIDS, severe malnutrition) history of hypersensibility to any of the study drugs or drugs used as alternative treatment (i.e. mefloquine, artesunate, quinine or tetracycline/clindamycin) suspicion of pregnancy or pregnancy (based on a urine pregnancy test).