India’s Prime Minister Narendra Modi wrote this week to Xi Jinping, offering the Chinese leader help in tackling the Wuhan coronavirus. Details of the assistance aren’t public, but Mr. Modi’s offer probably didn’t include supplies for a “treatment” that a senior Hindu fundamentalist advocated recently.

Swami Chakrapani Maharaj, president of the Hindu Mahasabha—a century-old organization that advocates Hindutva (or “Hinduness”)—declared that “consuming cow urine and cow dung will stop the effect of infectious coronavirus.”...