KK Women's and Children's Hospital (KKH) has apologised after it dispensed the wrong medication to a young girl by mistake.

The girl's mother Lau Jia Hui wrote on Facebook about the incident on Thursday.

In her post, she said her daughter Joey Tay was hospitalised from April 23 to 25. She did not say why her daughter was in hospital or how old the child is.

The photo posted showed a nasal spray meant for those under the age of three, and a bottle of nose drops.

The child was discharged on April 25 and pharmacy staff gave Ms Lau medicine to take home.

"Upon reaching home, as per instructions, I gave medicine to my girl," wrote Ms Lau. "Then KKH called and asked me to check on the nose spray and nose drop." She said the hospital told her to discard the medication as it had been opened and used before.

"We checked the medicines," said Ms Lau.

"To our dismay, my husband and I peeled off the nametag sticker of our girl and there's another patient's nametag sticker underneath."

Associate Professor Ng Yong Hong, head and senior consultant of the department of paediatrics at KKH, told The Straits Times yesterday that the hospital "apologises and fully empathises with the parents' anxiety".

She added that the hospital immediately contacted the family to replace the nose drops and isotonic saline nasal spray that were "mistakenly dispensed by the hospital's pharmacy to a patient".

"The patient was reviewed on Saturday and was well," she said. "A family meeting was done thereafter. We continue to remain in close contact with them."

Assoc Prof Ng said the hospital takes the matter very seriously.

"Investigations are being conducted and internal processes are being reviewed," she said.