A woman has been charged after an 11-month-old boy was given a bottle that was feared to contain bleach, police said.
Elaine Joyner is accused of administering a noxious substance with intent to endanger life.
The 53-year-old woman, of Deptford, south-east London, is due to appear at Bromley Magistrates' Court later.
Police were called to McDonald's in Eltham High Street, south-east London, after reports of a baby being taken ill at about 12.40pm on Thursday.
The child, who had been with his mother and grandmother in the restaurant, swallowed some of the contents and immediately vomited before being taken to hospital for observation.
Police do not believe anyone else was affected.