Giardia lamblia, the cause of human giardiasis, is among the most common intestinal protozoa worldwide. Human infection may range from asymptomatic shedding of giardial cysts to symptomatic giardiasis, being responsible for abdominal cramps, nausea, acute or chronic diarrhoea, with malabsorption and failure of children to thrive. At present, treatment options include the nitroimidazoles derivatives; especially metronidazole, which has been the mainstay of treatment for decades and is still widely used. The increasing number of reports of refractory cases with this group of drugs and other antigiardial agents, has raised concern and led to a search for other compounds, some of which have arisen due to the introduction of drugs initially addressed to other diseases. The present article examines some of the most important points of antigiardial pharmacotherapy available at present and the future prospects of development of new agents.