Final answer:
Diuretics are used to treat chronic high blood pressure by increasing urine production and reducing blood volume, leading to a decrease in blood pressure.
Step-by-step explanation:
Diuretics are used to treat chronic high blood pressure because they increase urine production, which leads to a decrease in blood volume and eventually a decrease in blood pressure. Diuretics work by inhibiting the reabsorption of sodium and chloride ions in the kidneys, causing more water to be excreted in the urine. This decrease in blood volume helps to lower blood pressure.