Plastic straws are commonly used for cold drinks, juices, milkshakes and packaged beverages. Yet social media posts often warn that chemicals or microscopic plastic particles released from a straw can enter the body and cause cancer. This sounds alarming, particularly because plastic pollution and microplastic exposure are genuine areas of scientific concern.
However, risk depends on the substance involved, the amount of exposure and how frequently that exposure occurs. Simply detecting a chemical or plastic particle does not prove that it will cause cancer. At present, there is no reliable evidence that occasionally drinking through a food-grade plastic straw causes cancer in humans.
Does drinking through a plastic straw directly cause cancer?
No. Current scientific evidence does not show that drinking through a plastic straw directly causes cancer.
Researchers have not demonstrated a higher rate of cancer among people who use plastic straws. In fact, there are no robust, long-term human studies establishing plastic-straw use as an independent cancer risk.
Plastic straws are generally manufactured from food-contact materials such as polypropylene or polystyrene. These materials must meet relevant food-safety requirements regarding the substances that can migrate from the plastic into drinks. Small amounts of chemicals may sometimes move from food-contact materials into food or beverages, but the presence of a substance alone does not make the exposure dangerous. The dose matters.
Cancer Research UK states that there is no reliable evidence from human studies that consuming food or beverages stored in plastic causes cancer. Laboratory experiments may find harmful effects when cells or animals are exposed to much higher chemical concentrations, but these conditions may not represent everyday human exposure. Cancer Research UK considers regulated food-contact plastics safe when used appropriately.
Can chemicals move from a plastic straw into a drink?
Yes, but usually in very small quantities. Chemical migration can occur whenever food or drink comes into contact with packaging, utensils or containers. It is not unique to straws or even to plastic.
Migration is influenced by several factors, including:
- The type and quality of plastic
- The temperature of the beverage
- How long the straw remains in the drink
- Whether the drink is acidic, oily or alcoholic
- Whether the straw is damaged, old or repeatedly reused
- Whether the product was manufactured according to food-safety standards
Heat can increase the movement of some substances out of plastic. This is why single-use plastic products should not be placed in boiling liquids, microwaved or exposed to temperatures for which they were not designed. Nevertheless, increased migration does not automatically mean that a cancer-causing dose has entered the drink.
Food-contact materials are assessed by estimating how much of a substance might migrate and how much a person could reasonably consume. Safety limits are then applied to keep exposure below levels expected to cause harm.
Do plastic straws contain BPA?
Not necessarily. Bisphenol A, better known as BPA, is mainly used to manufacture polycarbonate plastics and certain epoxy resins. It should not be assumed that every plastic object contains BPA.
Many disposable straws are made from polypropylene, while some are made from polystyrene or other polymers. These are different from polycarbonate. Therefore, describing every plastic straw as a source of BPA is inaccurate.
There is also scientific disagreement about the safety of BPA exposure. The US Food and Drug Administration maintains that BPA is safe at the levels currently permitted in food-contact applications. However, the European Food Safety Authority concluded in 2023 that dietary BPA exposure was a health concern, particularly because of possible effects on the immune system. The FDA and USDA have therefore reached different regulatory conclusions.
Importantly, this wider BPA debate does not prove that drinking through an ordinary disposable straw causes cancer. Actual risk depends on whether BPA is present, how much migrates and the person’s total exposure.
Can a plastic straw release microplastics?
Possibly. Microplastics are tiny plastic particles generally measuring less than five millimetres. Even smaller particles are often described as nanoplastics.
Plastic products can release particles through manufacturing defects, ageing, scratching, bending, friction and exposure to heat or sunlight. A damaged or repeatedly reused single-use straw may be more likely to shed particles than a new, correctly used one. Microplastics can also already be present in the beverage, water, packaging or surrounding environment, making it difficult to identify the straw as the only source.
Microplastics are now widespread in water, food, soil and air. This means people may swallow or inhale small plastic particles from multiple sources, not merely drinking straws. The World Health Organization has reviewed dietary and inhalation exposure to microplastics and emphasised the need for better-quality research to understand their effects on human health.
Have microplastics been linked with cancer?
Not conclusively in humans. Laboratory and animal studies suggest that some microplastics and nanoplastics may trigger inflammation, oxidative stress or cellular damage under certain experimental conditions. These findings provide valid reasons for continued investigation, but they do not establish that typical exposure from drinking straws causes cancer.
Cancer usually develops through a complicated interaction of genetics, age, lifestyle, environmental exposures and chance cellular changes. To prove that a particular exposure causes cancer, researchers need consistent evidence from human populations, credible information about dose and a plausible biological mechanism. That complete chain of evidence is currently missing for plastic-straw use.
Scientists are also dealing with major research challenges. Plastic particles differ in size, shape and chemical composition. Some carry additives or environmental contaminants, while others do not. Methods used to detect tiny particles are not yet fully standardised. Consequently, researchers cannot simply take the results from one type of plastic particle used at a high laboratory dose and apply them to all everyday plastic exposure.
The correct conclusion is not that microplastics are unquestionably harmless. Rather, their long-term effects remain uncertain, and there is currently no proof that exposure from using a plastic straw causes cancer.
Does using a straw with a hot drink increase the risk?
It may increase chemical or particle migration, but there is still no evidence that this exposure causes cancer.
Single-use plastic straws are usually intended for cold or moderately cool drinks. Placing one in a very hot beverage can soften or deform the material and may increase the release of certain substances. A straw that changes shape, develops an unusual smell or appears damaged should not be used.
The temperature of the drink itself deserves attention as well. Regularly consuming beverages at extremely high temperatures may injure the lining of the oesophagus. This risk is related to repeated heat damage, regardless of whether the drink is consumed through plastic, glass, metal or directly from a cup. Allowing very hot drinks to cool is therefore sensible.
What is the evidence-based conclusion?
Drinking through a food-grade plastic straw has not been shown to cause cancer. Small quantities of chemicals or plastic particles may potentially migrate under certain conditions, especially when plastic is heated, damaged or repeatedly reused. However, detecting these substances does not prove that the exposure is sufficient to produce cancer in humans.
Research into microplastics and chemicals used in plastic manufacturing is continuing, and reducing avoidable plastic exposure is a reasonable precaution. Still, the current evidence does not justify frightening people with claims that an occasional plastic straw will cause cancer.
For lowering cancer risk, attention should remain focused on well-established factors such as avoiding tobacco, limiting alcohol, maintaining a healthy weight, staying physically active, protecting the skin from excessive ultraviolet radiation and attending recommended screening. These measures have far stronger evidence than avoiding an occasional plastic straw.
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