Abstract: A detergent controlling mechanism for use in a toilet is configured to have a container having a first entrance defined through an outer periphery thereof, an adjusting apparatus having a third rod threadingly connected with the outer periphery of the container, a partition which securely and sealingly separates the container into an upper portion and a lower portion, a leverage having a fulcrum pivotally connected to a bridge and securely mounted onto the partition, an inlet valve having a first rod abutting a first end of the bridge and slidably received within a chamber of a second seat, a one-way valve for directing flow only from the first part to the second part and which is sealingly mounted on a board which separates the lower portion into a first part and a second part and a releasing valve mounted onto the partition for determining an amount of detergent to be released. The controlling mechanism is thus able to release a fixed amount of detergent to a water tank every time a user flushes the toilet.