Epilepsy Action said @TwitterUK’s new #DiscoverMusic campaign — which is designed to promote new artists and loops a six second clip of bright, flashing colors — was dangerous, as it could potentially produce seizures in people who have photo-sensitive epilepsy.

With 65 million people diagnosed worldwide, and Twitter’s extensive online presence, the ad represented a potentially serious problem. And “flashing bright lights or patterns” is a commonly reported trigger, according to the charity.

.@TwitterUK Your #DiscoverMusic Vines are massively dangerous to people with photosensitive epilepsy. Please take them offline now.

— Epilepsy Action (@epilepsyaction) July 10, 2015

“Marketing communications should not include visual effects or techniques that are likely to adversely affect members of the public with photosensitive epilepsy,” Advertising Standards Authority told the BBC.

The ad ran for a full 18 hours before it was pulled down.

Rachel Bremer, international communications director at Twitter (TWTR), responded to Epilepsy Action’s tweets:

@epilepsyaction @TwitterUK Hello, we appreciate your feedback, thank you. We have deleted them.

— Rachel Bremer (@ryb) July 10, 2015

Epilepsy Action later tweeted:

Thanks to @TwitterUK for removing their advert. We're happy to work with them to make future ads safe for people w/ photosensitive epilepsy.

— Epilepsy Action (@epilepsyaction) July 10, 2015

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