An Irish doctor working in Britain says women are more likely to be diagnosed with anxiety when they're actually having a heart attack.
Dr Hazel Wallace is founder of The Food Medic blog, a medical doctor, registered nutritionist and best-selling author.
She says there is a 'clear gap' on how men and women are treated in hospital.
She told Alive and Kicking even the guidelines being used are wrong.
"I started online as The Food Medic 10 years ago, and nutrition was my primary focus then.
"But as I left medical school and qualified as a doctor and was working with patients, I noticed that there was this clear gap between how we treat men and women in the hospital.
"And also when it comes to the guidelines we're using - they're based on research that is largely based on male bodies, male mice and male cells."
She says these guidelines are "simply extrapolated to a woman with the assumption that we're just smaller versions of men".
"[This] is completely untrue because we have these fluctuating hormones, we can get pregnant, physiologically we're just very different.
"We're built different - and are all of those things matter".
She says women also react differently to treatments than men do.
"We'll respond to treatments differently, we will present with symptoms differently - and we may require different forms of care.
"So I just dipped my toe into the research and realised actually there's a huge gap here.
"I realised women were being misdiagnosed, underdiagnosed, undertreated - like they weren't being heard".
'You'd never say a man's hysterical'
Dr Wallace says women are more likely to get a psychiatric diagnosis for a physical issue.
"It's almost as if women present with feelings and men present with symptoms.
"A lot of women feel like it's all in their head, or that people will just assume it's their hormones, and it's not really a real physical problem.
"And actually women are more likely to get a psychiatric diagnosis for a physical problem - so we're more likely to say it's anxiety when actually you're having a heart attack".
And she says how women are viewed in society needs to be changed.
"It's so archaic and it's based in a very made up diagnosis of hysteria: we say that women are hysterical, you'd never say a man's hysterical.
"Hysteria was this made up condition that was, basically, thought that it originated from the womb.
"In terms of the symptoms of that, it was everything from being a little bit tired, being a bit irrational, being manic, being sexually aroused or not aroused enough.
"It was just such random symptoms that these male doctors were imposing on women.
"And I still think that mentality hangs around a bit".