A container 10 for a liquid medicament suspension, e.g. an insulin crystal suspension, has a tube 11 with a sealing piston 13, a cap 16, and a mixing element 20 which moves along the tube 11 to assist mixing the suspension. The element 20 is guided by the inner surface of the tube 11 and has restricted lateral movement but is free to move axially, for example, by tilting or end to end inversion of the container. Flow passages such as apertures and peripheral recesses are provided in the mixing element which can serve to promote turbulent flow. The containers are particularly suited for use as multi-dose cartridges for pen-like injection devices or for portable infusion devices which have piston- operating mechanisms to co-operate with the container piston.