Children are mistaking dangerous laundry capsules for sweets at a rate of at least one incident every day, parents have been warned.
Incidents involving the often brightly-coloured liquid or gel detergent capsules are happening with "deeply alarming" frequency, and the Local Government Association (LGA) is warning parents to ensure they are kept out of children's reach.
The tablets contain a cocktail of chemicals which can cause serious harm if ingested, such as burn-related injuries, internal swelling, breathing difficulties or the risk of falling into a coma.
Exposure to the eyes can cause damage including temporary blindness.
Latest figures showed there was more than one incident every day involving laundry capsules and a child, usually aged under five , the LGA said.
A survey by the UK's National Poison Information Service found there were more than 2,000 recorded cases in five years.
Four children suffered breathing difficulties, one had a burned airway and four needed the support of a ventilator.
According to the most recent yearly breakdown of data on reported exposure in the UK, there were 404 cases in 2014, 424 in 2013, 422 in 2012, 434 in 2011 and 486 in 2010.
The LGA has joined forces with the Royal Society for the Prevention of Accidents (RoSPA) to raise awareness ahead of Child Safety Week next week.
LGA community wellbeing spokeswoman Izzi Seccombe said: "Councils with their responsibility for public health have concerns over the growing number of incidents involving a child and laundry capsules.
"Their brightly coloured appearance and small size mean a lot of children mistake them for sweets. If they bite into the capsule it will cause a cocktail of harmful chemicals to dissolve in their mouth and be ingested, causing serious harm.
"Keeping these tablets in a place where children can't access them, either locked away or in a cupboard they can't reach, would significantly reduce the chances of a young child getting hold of them.
"The frequency with which these incidents are happening - at least once a day - is deeply alarming and yet they can be easily prevented with a few simple steps of caution."
RoSPA public health adviser Sheila Merrill said: "All household chemicals should be stored either up high or in a lockable cupboard. Keep an eye out if you are doing the laundry while children are present too, as it only takes a second for them to get hold of one."