He Shall, from Time to Time - S1-E12
C.J. Cregg: What are you taking?
President Josiah Bartlet: I don't know. My wife hands me pills, I swallow them with water.
Sam Seaborn: Sir?
President Josiah Bartlet: Vitamin C, Vitamin B. Is it possible I'm taking something called euthanasia?
Sam Seaborn: Echinacea?
President Josiah Bartlet: Ah, that sounds more like it.
Answer: It's in reference to the many televangelists and revival ministers usually associated with the right-wing that have been convicted of tax fraud (Jim Bakker and Tamy Faye being a more famous set). Occasionally, the more unscrupulous ministers have bilked millions from believers all in the name of God.
Nikki