Updated 18 October 2026.
When Hong Kong's Consumer Council tested 20 baby teethers, it found two that contained cancer-causing chemicals called nitrosamines, or the substances that can turn into them.1 In one teether, the precursors seeping out measured 0.94 mg/kg, more than eight times the maximum limit in EN 71-12, the European toy safety standard for these chemicals.1 That unit, mg/kg, means milligrams of chemical for every kilogram of material: a scale for traces far too small to see. Yet 0.94 mg/kg is below 1 mg/kg, the ceiling British law sets for these substances in toys for young children, so the same teether would have been within the legal limit here.1,2
These chemicals come from the way rubber is cured: some of the helper chemicals used to speed up curing, called accelerators, can turn into nitrosamines in natural and synthetic rubber alike.3,4 So the word "natural" on a teether tells you where the rubber came from; only a test of the finished toy shows what comes out of it when a baby chews.
Germany's Federal Institute for Risk Assessment is careful to say that "the occurrence of a substance in a toy does not necessarily mean that there is a health risk": what matters is whether it is released and how much can enter the body.5 But for several nitrosamines it says no safe threshold can be set, because "even trace quantities of them can cause cancer".3 We found no report of a child made ill by a rubber toy. The concern is that these traces can reach a baby's mouth, and for several of them no safe amount has been set.
The same institute says that forming these chemicals "can be widely avoided through the choice of suitable vulcanization accelerators".3 YAN's view: a rubber toy a baby chews should be made to the strict EN 71-12 limit, because having no evidence of harm is not the same as having evidence of safety.
What you need to know
- A CE or UKCA mark means the maker declares the toy legal; for the strict limit, look for EN 71-12 on the packaging or product page.
- If the packaging doesn't say, a one-line question to the seller covers it.
- Free comfort comes first: a clean finger on sore gums, a cuddle, a game.
Where the chemicals come from
Natural rubber starts as latex, the milky sap tapped from rubber trees. Turning that soft sap into springy, durable rubber relies on vulcanisation, a curing process Charles Goodyear invented in 1839.6 Accelerators speed that curing up, and during the process some of them change into nitrosamines and some into precursors.1,3
Hong Kong's Consumer Council explains that these precursors may be converted into cancer-causing nitrosamines in an acidic place such as the stomach.1 That is why the tests look for both: the nitrosamines already there, and the precursors that could turn into them.
Chemicals leave a toy above all when it is put in the mouth, so the tests soak the rubber in a liquid made to behave like saliva and measure what seeps out.5,7 People take in nitrosamines mainly through food such as smoked and pickled meat, but the German institute points out that rubber toys small children put in their mouths can be a specific source.3 Parents can't do much about every source, but a teether is one they choose, and one a baby may hold in the mouth for long stretches.
Can makers keep these chemicals out?
In the spring of 1981, a German study presented at a meeting of the American Chemical Society reported nitrosamines in rubber baby bottle nipples.8 The US Food and Drug Administration followed up, found nitrosamines in rubber nipples sold in America, and showed they could seep into milk and infant formula during ordinary sterilising.8
According to the FDA, "Manufacturers altered product formulas and manufacturing processes to reduce nitrosamine formation."8 Today, one rubber-chemicals supplier sells an accelerator for natural rubber that it describes as nitrosamine-free.9 Which means a rubber teether doesn't have to carry these traces; what a parent needs is a way to spot one that doesn't.
Why toys for babies got a stricter test
When Europe rewrote its toy rules, the new limit for rubber toys for under-threes matched the one Germany used for balloons, which is higher than Germany's own limit for toys.3 The German risk institute warned that this could weaken protection, and gave a reason any parent will recognise: "small children put toys into their mouth more frequently and keep them there for longer than they do with balloons".3
Its advice was simple: Germany's "lower limit values should be maintained".3 In 2016 the European toy standard for these chemicals, EN 71-12, caught up: it added a stricter set of limits for rubber toys meant for under-threes and likely to be mouthed, identical to the German ones.10
What the rules say in Britain
British law bans nitrosamines and their precursors in toys for children under 36 months, and in other toys meant to go in the mouth, once the amount released reaches a set ceiling.2 A UK government notice lists EN 71-12 among the standards it recognises for toys and notes that its limits are lower than the law's: 0.1 mg/kg of precursors, where the law allows 1 mg/kg.1,11,12 Those lower limits are for rubber toys for children under 36 months that are "intended or likely to be placed into the mouth".10
A teether is made to be chewed, so it is exactly the kind of toy the lower limits were written for.
Following the standard is one way for a maker to show a toy complies, but the government says such standards "do not replace" the law, and makers "retain full responsibility" for meeting it.12 Some toys need a check by an independent third party, but for the rest the maker can put a CE or UKCA mark, the marks you see on toy packaging, on the toy on its own say-so.13
What tests of real products found
Sophie la girafe is a rubber giraffe made from the latex of the Hevea tree.6 Being made from a tree does not, on its own, make a toy safe to chew.
The dispute was over a stricter German limit: Vulli, the maker, at first answered that another regulation applied, the EU guidelines for toys.14
Then Vulli recalled Sophie the Giraffe and similar toys from German retailers and offered a swap: one made on or after March 2012, which it says meets the stricter German limit.14 Which means even the maker did not claim the older giraffes met that limit. In the end, the whole argument was over which limit a teether should be held to.
This investigation continues below.
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That is why the test that matters is on the finished toy, because the rubber in it is what ends up in a baby's mouth.
In a Korean study of baby bottle teats and rubber kitchen tools, nothing exceeded the permitted limits, and, in the authors' words, "All tested products were considered safe for use".15 Meeting a strict limit is real protection, and well-made rubber shows it can be done.
The gaps in the testing we found
We found no recent test of natural rubber teethers sold in Britain, and no study measuring how much of these chemicals a baby actually takes in from chewing one. The Hong Kong report doesn't say what its two teethers were made of, none of these sources compares rubber with plastic or silicone, and most of the stories are years old, so the products in them may have changed since. What would change our view is an independent survey of today's natural rubber teethers showing they routinely meet the strict standard; then the word "natural" on its own would tell parents far more than it does now.
What to choose
Unless someone in your home has a latex allergy, we prefer natural rubber to plastic for a teether; none of this evidence compares the two, so it gives no reason to switch either way. Start with what costs nothing: the NHS says comforting or playing with a teething baby can distract them from the pain, and gently rubbing their gums with a clean finger may also help.16
When you buy, check the basics: British rules require a toy to show who made it, with a contact address, on the toy or, where that isn't possible, on its packaging or in an accompanying document.13 Skip any teether with no maker's name and no CE or UKCA mark: it gives you no sign it meets even the legal ceiling, which makes it the worst choice on offer.
Better is a natural rubber teether from a named maker with a CE or UKCA mark. The one exception: if your baby or anyone in your home has a latex allergy, or your GP has said your baby is at higher risk of one, skip natural rubber and ask your GP which latex-free teether to choose. Best is one whose packaging or product page says it meets EN 71-12, the strict standard for rubber toys babies put in their mouths. If the page doesn't say, one short question to the seller covers it: "Does this teether meet the EN 71-12 limits for rubber toys for under-threes that go in the mouth?"
If you already have a rubber teether and can't find out, there's no need to bin it in a hurry; offer other comforts too, so it isn't the one thing chewed for hours, and choose the stricter option next time.
If your baby likes something cold, the NHS says some rings can be cooled in the fridge first, and the instructions that come with the ring should tell you how long to chill it.16 So chill the ring in the fridge for the time its instructions give, and hand it to your baby loose, never on a cord. At YAN we would buy only a rubber teether made to the strict standard, because a teether spends hours in a baby's mouth.
Next time a teether goes in the basket, turn the box over first: if EN 71-12 is on it, that is the strict standard; if it isn't, pick one that says it.