Thanks for query,
It seems that this may be due to constipation
,If you give some Iron tonic then stop giving for few days as Iron can produce constipation.
You can give light laxative if require.
some times in children there may be worn infection may give rise to this problem so go for stool test
for ova and cyst
and other bacterial infection.
After report go for the treatment.
Give her plenty of water and green vegetable soup.
Ok and bye.