Compton Care's Retail Plus shop and hub was broken into on Sunday night and will be closed until further notice, depriving patients of vital support sessions.
Staff at the Snow Hill store, which raises money for people with incurable conditions, are working tirelessly to clean up the flood damage and get the premises in a fit state to reopen.
Rachel Overfield, Compton Care’s chief executive officer, said: “An act of vandalism such as this has a huge impact.
"Not only does the shop raise much needed funds so we can deliver our vital care, but it is also where we host support sessions for people living with incurable conditions, as well as bereavement support for the community.
"These sessions will sadly have to be postponed until we are able to open our doors again. The local community has always been a huge support to us, and we hope to welcome you back in no time. We’ll be keeping our supporters up to date via our social media channels.”
Compton’s network of shops raise in excess of £900,000 each year to help local people living with incurable conditions.
The charity's Facebook page was inundated with messages of support after Compton Care revealed the extent of the damage at the shop.
Mick Painter said: "I just hope the people I use this term loosely who did this don't need your care at some point and cant get it because some half wit has destroyed your way of raising much needed funds I think they would call that karma."
Jane Williamson added: "That's terrible news. There really are some horrible people out there. If they had any appreciation of what amazing work you do and where your funding comes from. This makes me angry."
Kathleen Anslow said: "Disgusting! Have people no morals, it’s a charity shop for goodness sake."
West Midlands Police has been contacted for comment.