Giardia lamblia is one of the most common intestinal parasites of children. Most infections are asymptomatic and do not require treatment. If persistent diarrhea or wasting is present, antimicrobial treatment is required. Because repeated infections are possible, elimination of cysts from the environment is important to prevent further transmission. G lamblia is particularly common among children participating in group activities (ie, day care centers) and is a special threat to immunosuppressed children. Diagnosis usually is made by microscopic examination of stool. Standard treatment of symptomatic infections is with furazolidone or metronidazole. Copyright © 2000 by W.B. Saunders Company