Parents were cautioned to not medicate children under 6 with over-the-counter cold remedies as apart from not working these medications can cause side effects like hallucinations.

Chemists have also been banned by watchdogs from selling more than 60 brands over fears of harmful side effects. They said the cold cures could cause allergic reactions, sleep disturbance and hallucinations

The Medicines and Healthcare products Regulatory Agency (MHRA), reviewed many such remedies such as Lemsip, Day Nurse and Sudafed and found "no robust evidence that these medicines work" in children. They said simple home remedies like honey and lemon mixtures to ease a cough were a safer and better option for children. Spokesman Dr June Raine said, “Coughs and colds are distressing but will get better by themselves in days.”

The MHRA added that due to the possible side effects many of these medications can no longer be sold for use on children under six and new and clearer advice will be published on packets for children between six and 12.

Certain medications that are excluded from the new rules include Calpol, which is a pain relief preparation used to lower a child’s temperature. The MHRA recommends for children under six parents should stay with safer home remedies like keeping the temperature down and home remedies for a cough and cold. Sally Russell, who runs a parenting advice website, said, “This is going to be very confusing for parents.

Pharmacy chain Boots said, “As the owner of Boots branded medicines and as a responsible retailer, we will be following the MHRA guidance.”