A woman has been arrested after an 11-month-old boy was given a bottle feared to contain bleach as he sat in a fast food restaurant in south-east London.
The toddler was with his mother and grandmother in a McDonald's on Eltham High Street, when he drank from the bottle at about 12:45 BST on Thursday.
He was taken to hospital, where his condition has been described as stable.
Detectives arrested a 53-year-old woman in Deptford, who is being questioned at a south London police station.
The boy immediately vomited after swallowing some of the contents, Scotland Yard said.
Officers later recovered the bottle and tests are being carried out to find out what it contained.