A student who was accused of taking drugs while using a disabled toilet at a Wetherspoons pub is calling for better awareness of invisible disabilities.
Amber Davies, 21, from Builth Wells, has a stoma after being diagnosed with ulcerative colitis aged 13.
While on a night out in Birmingham, she was "grabbed" by a bouncer after coming out of the disabled toilet.
Wetherspoons said staff apologised for the "confusing situation".
Amber posted an open letter on her Instagram account detailing her experience, saying the door staff "very happily and very openly accused me of snorting, dealing and having sex in the disabled toilet for 'there is no other reason I would need to visit it so often'".
"I got grabbed by a female bouncer and my boyfriend by a male bouncer, we were accused of using them [the disabled toilet] for the wrong reasons," Amber told the BBC.
"She [the bouncer] was quite reluctant to listen to my side of the story, I said it bluntly and I didn't raise my voice once."
Despite gaining access to the locked disabled toilet using a radar key, staff "kept shouting" and her boyfriend, who had gone in the toilet with her, was taken outside.
"I was upset at the time, we hadn't done anything wrong, I spoke well considering. I was more annoyed that people were allowed to behave that way," she added.
"[It's] just completely unacceptable and they're such a big chain, you'd think they'd have training or be knowledgeable before grabbing us."
Amber, who is about to start her third year at Cardiff University, said she had come to expect "funny looks" but not the kind of treatment she received at the Dragon Inn in Birmingham.
In her post she said her stoma "needs constant care" and can be emptied up to 15 times a day, "it can make going out, especially on nights out, a pretty daunting prospect".
The 21-year-old described her disability as a "chronic, debilitating, lifelong illness".
She contacted the chain to complain about her treatment and has been offered a gift card in response.
A JD Wetherspoon spokesman said: "A female member of door staff spoke with Ms Davies, who explained her disability.
"Staff expressed that if this had been known beforehand, or an explanation given sooner, the situation could have been avoided.
"Staff listened at length to Ms Davies' points, never once questioning her disability and apologised for the confusing situation on both sides."