The recall is necessary due to a risk of mould gathering in the cups' valve, which is said to have led to diarrhoea and vomiting. The mould cannot be seen while cleaning the cups.
Ass many as 70 children are reported to have become ill so far, with the manufacturer recalling more than three million items in the USA.
UK customers have been advised to stop using the cups for now and wait for a version with a two-piece valve which the company claims will be easier to clean.
There is more advice on the Tommee Tippee website including a guide on how to clean the one-piece valve cups, http://www.tommeetippee.co.uk/support/faqs/one-piece-valve-cup/|find out more at tommeetippee.co.uk|go to www.tommeetippee.co.uk