Is the child lethargic, still vomiting , having fever ? If yes you need to consult a pediatrician near you . If no , then nothing to worry this is transient and probably secondary to poor oral intake over 1-2 days . Just give him fluids soft foods and monitor for any danger signs.

Greetings Emset (ondansetron) commonly causes constipation in children as a side effect.The lack of bowel movements since Monday is likely due to this medicine.Do not give general laxatives without consulting your pediatrician first.Encourage your child to drink plenty of fluids and water to stay hydrated.Offer small, frequent amounts of bland foods or liquids since appetite is low.

Dont worry sometimes there will be sudden constipation in kids. If your kid is active playful taking feeds well nothing to worry You need to give more liquids to pass stools and give more fibre Rich diet like Apples, Bananas

If your child is active, passing gas, has no abdominal swelling and vomiting has stopped, this is usually not serious and may occur after a stomach infection due to reduced food intake. Encourage fluids and soft foods. A stool softener such as lactulose may help. However, if abdominal distension develops, vomiting recurs, severe pain occurs, or the child is not passing gas, please seek urgent pediatric evaluation.