Multi-unit delivery system

An active agent dispenser for use in a fluid-containing environment comprising, in combination:

• a. a rigid housing open at one end to provide outlet means therefor, at least a portion of said housing proximate the end of said housing opposite the outlet means permitting passage of the fluid in said environment to the interior of said housing;
• b. a fluid-activated driving member within said housing in fluid transmitting relationship with the fluid passing portion of said housing proximate the end of said housing opposite said outlet means, said driving member, upon exposure of said dispenser to said fluid environment, being the source of motive power for moving the contents of said housing through said outlet;
• and
• c. a plurality of solid, discrete active agent dosage units containing the active agent longitudinally disposed within said housing between said driving member and said outlet means, whereby said active agent units will be sequentially displaced from said housing into said fluid environment by said driving member upon exposure of said dispenser to said fluid environment, at least a portion of said active agent units being adapted to maintain their chemical and physical integrity while within the housing and to dispense a substantial portion of their active agent content into the fluid environment after their displacement from said housing into said environment.