Scientists from McGill University in Canada tested four commercial tea bags.
They removed the tea from the bags to make sure it didn't skew the results and then put the bags into boiling water to simulate brewing tea, CNN reported.
They found that a tea bag released 11.6 billion microplastic particles and 3.1 billion nanoplastic particles into a cup.
To put it in perspective, the smallest plastics measured 100 nanometers while a human hair is about 75,000 nanometers, according to McGill scientists.
The experts said the results were thousands of times higher than the amount of plastic found in other foods and drink.
They are now calling for more studies since the health effects of drinking the micro and nanoplastics are unknown.
Researchers who conducted a different study earlier this year said that people eat about five grams of plastic each week, or about a credit card's weight, CNN reported in July.
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The World Health Organization said last month that microplastics "don't appear to pose a health risk at current levels" when the group looked at health risks of plastic in tap and bottled water, but said that more research was needed, CNN reported in August.
For more information on McGill's research, click here.