The present invention relates to a multi-chamber bag. In all embodiments at least two different concentrates can be included separately in powder form, liquid form or semi-liquid slurry form for dissolution in a fluid in the multi-chamber bag. The present invention also relates to the use of the multi-chamber bag in haemodialysis or peritoneal dialysis or a haemodialysis or peritoneal dialysis device, in particular as a container for a dialysis fluid in a haemodialysis or peritoneal dialysis device.