A 4-year-old girl was hospitalised with constipation because her school's toilet roll rules left her too scared to relieve herself when she used the bathroom.
Cardiff school Kitchener Rd Primary refuses to put toilet paper in the student cubicles.
Instead, the school makes the students aged between 4 and 11 take what they think will be enough paper from a single dispenser before going to the bathroom.
The girl's mother, Fahmin Khanum, said the policy has meant many children have soiled themselves and others are too anxious to use the bathroom.
Khanum revealed her 4-year-old was taken to University Hospital of Wales for three days in October with intense stomach pains.
Medics eventually diagnosed the young girl with constipation, something she had never suffered before.
Her mother says she has been potty trained since aged 2-and-a-half and has never had any toileting issues until now.
"She was not clearing her bowels properly in school because of the toilet paper policy. It was a traumatic experience.
"My daughter is quite independent from going to day nurseries before starting school in September and she was potty trained at two and half and had not had problems before."
Khanum was only made aware of the school's policy after attending a parents' evening. Her daughter explained she was too scared to go to the toilet in case she got the amount of toilet paper she needed wrong.
It has since caused her daughter to become anxious whenever she uses the bathroom, even at home.
Last week, according to Wales Online, her daughter had soiled herself at school.
"You can imagine you run out of toilet paper and you know you might need to take your pants down and go to the public area and go back in, or pull you pants back up and soil yourself going out to get more paper.
"This is what happened to my daughter and she then had to go and tell a teacher in front of other children that she had soiled herself."
The school has since responded, telling Wales Online they're reviewing their policy.
"We have reviewed our policy and will soon be installing dispensers in all our cubicles. We will be contacting parents shortly to let them know of the change."