Abstract: A mattress, which is particularly effective in preventing and relieving decubitus ulcers, comprises a plurality of inflatable sections. Inflation means associated with the mattress inflate at least one of the inflatable sections at a first, higher pressure and simultaneously inflate at least one of the inflatable sections at a second, lower pressure. By sequentially changing the sections to which the high and low pressures are applied, different areas of a patient's body may be pressure relieved in turn, allowing blood to flow in the parts of the patient in contact with a low pressure section, while still providing support for the patient. There may be a number of groups of sections, all the sections in each group being interconnected, and each group being sequentially inflated at the lower pressure for a preset period.