Hello dear user! I have gone through your query and understood your concerns! Thank you for sharing them on healthcaremagic. Zentel may be used to parasitic infections such as round worms, tape worms, giardiasis, trichuriasis etc, in kids at your sons age at dosage 15mg/kg a day. For example if your son is 15kg you can give him about 200mg a day. I would not recommend medication more than 3 days. 3 days with 200 mg every day would be enough. You can repeat the cure after 3 weeks again to ensure the infection is removed. You can give the medication once a day usually at evenings or bedtime or divide it in two doses of 100 mg each of them (morning/evening). I hope this answer was helpful to you! Please kindly rate it and write a short review about your experience with me! Thank you and best regards! DR ERIOL.