The charity plans to send out tens of thousands of postcards to stop people moving the red cord, which allows disabled people to call for help in an emergency.
Cords are often moved when cleaners are mopping the floor or to keep out of children’s reach, but this can put future users at risk.
After the campaign was mentioned on BBC Radio 2’s Jeremy Vine show, the charity said it has received requests for almost 5,000 postcards.
The pocket-sized card is designed to be attached to the cord and reads: “This red emergency cord must hang freely all the way to the floor. If it does not, it may prevent a disabled person from asking for help.”
Euan’s Guide co-founder Euan MacDonald encouraged both individuals and companies to get involved with the scheme.
He said: “We want a Red Cord Card in every accessible toilet in the UK. If a cord is tied up, wound around grab rails or cut short it prevents a disabled person calling for help.
“Please free the cords when you see them tied up and place a Euan’s Guide Red Cord Card on them.
“It may seem like a small thing but it is often the small things in life that make things so much easier for disabled people.”
The charity has already sent out more than 40,000 cards and wants to see all disabled toilets become safer by the next World Toilet Day on 19 November 2019.
Its campaign is the largest of its kind to physically improve safety for disabled people without requiring any kind of construction or building alteration, it said.
Pubgoers said they had experienced some pubs using their accessible toilets as storage spaces in a survey by Euan's Guide, The Morning Advertiser reported last year.
Venues can request postcards on the charity's website and will be sent them free of charge.