Children with constipation is not advisable to self treat. Reason can be multiple ans some very serious. Go to a hospital and get a consultation with tests as advised

In this age group such problems are common die to following reasons: Milk predominant diet Less water intake Less intake of fiber For mow you can give syrup cremafin 2.5ml or lactulose syrup 3ml at bed time... Focus on the childs diet to prevent such problems

Give high fiber diet. Maintain proper hydration

Constipation is common in child of that age due food changes over activity etc instead of a medicine try some natural remedies like munnaka in milk increase fiber intake avoid more chocolates etc.if no improvement in three to four days than consult on line.

Constipation is very common in children as diet switches from one to another type of foods and it’s adaptation. The culprit in many cases of toddler constipation is a diet that's too heavy in processed foods, dairy, and sweets, and too light in fiber (like whole grains, fruits, and vegetables). Not getting enough fluid can also lead to constipation, because it makes the stools harder.