Thank you for your query on Healthcare Magic.
Passing of stool into clothes is called encopresis.
It is mostly due to constipation
and retention of stool.
Your child is suffering from constipation with fecal retention
due to which is not able to evacuate stool completely and passing stools into underwear.
I advise you to treat the child constipation first and once the constipation is being treated this problem will resolve.
Give dietary fiber
rich food by giving cereals, legumes, vegetables, leafy vegetables, and fruits on daily basis.
Ask her to sit in the toilet daily for 5 to 10 minutes.
Encourage her to take plenty of oral fluids and water.
If there is still constipation and fecal retention, retention and fecal impaction
should be treated by putting laxative suppository and oral stool softeners like lactulose in prescribed dose.
So consult the Pediatrician
for examination for fecal retention and for management of child problem.
Hope I have answered your query.