Chocolate maker Mars has ordered a recall of chocolate products in 55 countries.
In the UK the products affected include funsize Mars and Milky Way bars and boxes of Celebrations.
In the Netherlands Mars and Snickers bars were also affected.
It comes after a customer in Germany found bits of plastic in a Snickers bar in January. The plastic was traced back to the Mars factory in the southern town of Veghel in the Netherlands.
A Mars Netherlands spokesperson said: "We cannot be sure that this plastic was only in that particular Snickers. We do not want any products on the market that may not meet our quality requirements, so we decided to take them all back."
The recall only involved products manufactured at the Dutch plant.
It covers mostly countries in Europe and does not extend to the US, where Mars is based.
The company has not said how many bars are affected or how much the recall will cost.
The UK's Food Standards Agency (FSA) advised consumers not to eat the affected products and to contact Mars' consumer care team on 0800 952 0084, firstname.lastname@example.org or by post at Mars R1, FREEPOST, Mars Consumer Care.
The products in the UK include Mars, Milky Way, Snickers and Celebrations in various package sizes:
* 250g bags of Mars Funsize (product code AV39F) with a best before date from 11/09/16 to 02/10/16
* 227g bags of Milky Way Funsize (product code AV39J) with a best before date of 02/10/16
* Variety Funsize - Family Favourites (product code AV33W) with a best before date from 29/05/16 to 14/08/16
* Variety Funsize - Party Mix (product code AV33T) with a best before date from 15/05/16 to 07/08/16
* 388g boxes of Celebrations (product code AJ46N) with a best before date from 08/05/16 to 28/08/16
* 245g boxes of Celebrations (product code AJ46R) with a best before date from 08/05/16 to 28/08/16
* 2.5kg catering cases of Snickers Miniatures (product code YF413) with a best before date of 07/08/16 and 14/08/16
Mars is one of the world's biggest food companies, with 29 chocolate brands including M&M's, Galaxy, Twix, Bounty and Maltesers. It also makes Wrigley gum, Uncle Ben's Rice, Dolmio pasta sauce and Pedigree pet food.
The company is one of the largest privately owned businesses in the US and had global sales of $33bn last year.