Since Fidji Simo joined OpenAI in mid-2025, her work has been nonstop. What started with the title “CEO of Applications,” with a focus on commercializing OpenAI’s technology, quickly became much more than that.
OpenAI essentially split its organization in two, with Simo overseeing much of the company’s core business while CEO Sam Altman focuses on research and compute. In less than a year, Simo has shepherded the introduction of advertising into ChatGPT, the ongoing creation of an AI “superapp,” the introduction of ChatGPT Health, and the surprise acquisition of the tech news show TBPN. That’s hardly a complete list of her responsibilities; her title is now CEO, AGI deployment.
It’s a remarkable remit for any executive, and becomes all the more so when you learn more about what Simo has been navigating at the same time. OpenAI announced on Friday that Simo would be taking medical leave from the company for “the next several weeks.” Simo has the neuroimmune condition POTS, and experienced a relapse a few weeks before she started at OpenAI. “For my entire time here, I’ve postponed medical tests and new therapies to stay completely focused on the job and not miss a single day of work,” she wrote in a memo Friday. “I took time off for the first time two weeks before the break for some medical tests, and it’s now clear that I’ve pushed a little too far and I really need to try new interventions to stabilize my health.”
Simo has long discussed women’s health, including while she was CEO of Instacart and a Facebook exec. In 2021, she launched an organization called the Metrodora Institute that was built to better integrate care for patients with neuroimmune disorders, especially women. It closed shortly before Simo joined OpenAI; its nonprofit arm is still operating and was rebranded as the Complex Disorders Alliance. Over the past few days, she has posted on X about her medical leave, now that there’s even more interest in her status due to the consequential nature of her job. “If there is one good thing that can come out of having my health issues exposed to the world, it’s raising awareness for complex chronic conditions like POTS, MECFS, Long Covid or EDS,” she wrote, sharing a link to a news article headlined, “What is POTS, the disorder that forced OpenAI exec Fidji Simo to take medical leave?” She’s drawn connections between her work and her health: “I have high hopes that AI will accelerate the path to cures, but patients cannot wait,” she wrote. “Despite all the resources at my disposal and an incredible support system, I still couldn’t avoid a medical leave. We need better solutions for all patients, now.”
Simo’s news wasn’t the only unfortunate update for OpenAI’s executive team. OpenAI CMO Kate Rouch is stepping down to focus on her recovery from breast cancer; she was diagnosed shortly before she stepped into the job. She echoed a similar theme as Simo: “You can’t outwork your body,” she wrote on LinkedIn. “At a certain point, you have to be honest about your limits. I’ve reached mine.” Rouch plans to return to a role with narrower scope when her health allows, while OpenAI searches for a new CMO.
As OpenAI is preparing to become a true, mature tech giant (and go public), it’s tapped a growing group of executives, many of them women. It’s a sad coincidence that two were faced with serious health challenges so shortly before beginning what they likely view as a once-in-a-lifetime opportunity. Simo wrote in her memo: “The timing is maddening because we have such an exciting roadmap ahead that the team is executing on, and I hate to miss even a minute of it.” Both Simo and Rouch are sharing more about their experiences than would be required or typical—something we often see from female execs.
While OpenAI stresses that it has a strong executive bench that is more than capable of executing in Simo’s absence, you only need to take a look at the long list of execs tapped to step in to understand her importance to the business. Cofounder Greg Brockman will lead product, while CFO Sarah Friar, chief revenue officer Denise Dresser, and chief strategy officer Jason Kwon will all take on aspects of Simo’s work.
“I can’t wait to be back in the arena with you all soon,” she wrote.
Emma Hinchliffe
emma.hinchliffe@fortune.com
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