A canister arrangement for refilling a pharmaceutical dispenser. The dispenser can hold a predetermined number of pills, tablets, or capsules at one time. Since the canister arrangement can hold considerably more than the dispenser can, the canister is able to fill the dispenser to capacity multiple times before the canister must be refilled. The canister has a housing and one or more chambers in the housing. When a plurality of chambers is present, at least one of the chambers has a sloping floor at the bottom of the housing. A swinging door is disposed between each pair of adjacent chambers. The swinging door(s) are automatically activated when the dispensing apparatus senses that the dispenser and the previous chamber are both empty. An opening is also provided at the bottom of the housing. A sliding door covers the opening to prevent pills, tablets and capsules from exiting the housing. The sliding door is automatically opened upon the occurrence of an external condition, such as when the dispensing apparatus senses that the dispenser is empty.