Two schoolboys from a non-endemic region visited an endemic area of Schistosomiasis in Yemen. They developed cutaneous itching after swimming in infected ponds. Five weeks later both brothers were admitted to the hospital with high fever, abdominal pain, vomiting and diarrhea. The blood results exhibited marked eosinophilia and schistosomal serological test showed an evidence of exposure. Initially, stool examinations were negative, but the sigmoidoscopy was suggestive for acute bilharzial colitis and the biopsy showed schistosoma ova; a finding consistent with Katayama syndrome. Both patients treated with Praziquantel, and they became asymptomatic, and the eosinophilia normalized. This report shows the importance of endoscopic and histological examination in suspected acute colonic schistosomiasis, which allows early treatment and avoids possible complications.