Hi... The best treatment options for Giardiasis is - tinidazole, metronidazole, or nitazoxanide. Patients with giardiasis should be counseled to avoid lactose-containing foods for at least one month after therapy. Treatment is not usually recommended for asymptomatic individuals. However, treatment may be warranted to prevent the spread of infection if a patient is a household contact of a pregnant woman, an immunocompromised individual (especially in the setting of hypogammaglobulinemia), or a child in a day-care or other setting who might transmit infection to others. Regards - Dr. Sumanth