Driclor contains aluminium chloride hexahydrate, an antiperspirant that stops you sweating.
When you apply Driclor to the skin, its active ingredient (aluminium chloride) works by blocking the sweat glands. This causes a build up of pressure of fluid within the sweat glands to the point where they stop sweat production for some time. Driclor is usually applied before going to bed at night in order to block the sweat glands while they are least active and washed off in the morning. The sweat glands will then remain blocked and so will not produce sweat during the day.