Actress Claire Foy explains how she figured out that she had parasites — and what she did to recover.

The Crown star Claire Foy reveals she battled parasites for 5 years: ‘I didn’t know what was going on’

Actress Claire Foy explains how she figured out that she had parasites — and what she did to recover.

By Raechal Shewfelt

Raechal Shewfelt

Raechal Shewfelt is a writer at **. She has been working at EW since 2024. Her work has previously appeared on Yahoo and in American *Journalism Review* and *The Shreveport Times*.

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February 4, 2026 6:07 p.m. ET

Claire Foy in New York in 2026. Credit:

John Nacion/WireImage

You won't see British actress Claire Foy drinking tea, at least not the caffeinated kind, thanks to a scary episode with parasites.

Foy, who famously played Queen Elizabeth II in the first two seasons of *The Crown*, was asked when she stopped drinking caffeine during a visit to the *Table Manners* podcast.**

"Quite a few years ago," the actress said. "I had parasites. Gross. Shouldn't bring that up."

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But hosts Jessie and Lenni Ware were fascinated and asked the actress whether she learned of her diagnosis from a blood or stool test.

Foy confirmed it was the "gross stuff," and said she'd realized something was off with the amount of food she was consuming.

"I kept losing weight, and I didn't know what was going on," Foy said. "I was just like, 'I'm eating everything.' I was so hungry."

Claire Foy on 'The Crown'.

Alex Bailey/Netflix

The star of movies including *First Man* and *Women Talking* was confident that she had picked up the parasite while in Morocco.

By the time she was diagnosed, Foy said, she'd had the parasite for "at least five years. And they travel as a pair, I got told by the doctor. Gross. Absolutely rank. It's disgusting."**

"Parasites are organisms that live in, on or with another organism (host)," according to the Cleveland Clinic. While they "rarely kill their host," they "often carry diseases that can be life-threatening." People can get parasites in ways including spending time in areas with them, from contaminated food or water, or from bug bites.**

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They can cause symptoms such as nausea and vomiting, diarrhea, fatigue, skin rash, and, to Foy's point, increased appetite and unexplained weight loss.**

"Anyway, so that's why I gave up caffeine, because I basically had to go on this diet — because I didn't want to take really hardcore antibiotics and stuff like that for it — I took all this gross stuff, and part of that was giving up caffeine. And once you've given it up — it's such a mission to give it up — that I was like, well maybe I'll just give it a go of not."

She said that withdrawal from caffeine was rough because it was something she had enjoyed consistently.**

"I drank at least 15 cups of tea a day, and then I had my two coffees," Foy said.**

Listen to the full conversation above.**

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