Back in 1970, India withdrew drug patents in order to support its generic-drugs industry. They were reintroduced, with caveats, in 2005 when the country’s entire intellectual property regime was updated to comply with World Trade Organization rules. Acting on the advice of public-health activists, a group of Communist parties that formed an indispensable minority of the governing coalition forced the Congress Party to go along with the innovation-friendly restrictions that remain today.

Last month, when the B.J.P. announced its new intellectual property policy, it in effect repeated India’s longstanding response to its critics: Tough luck; our patent laws comply with W.T.O. standards, and that’s that. Or, as Mr. Modi himself put it when he addressed the U.S. Congress last week: “India’s ancient heritage of yoga has over 30 million practitioners in the U.S. It is estimated that more Americans bend for yoga than to throw a curve ball. And no, Mr. Speaker, we have not yet claimed intellectual property rights on yoga.”

But there’s yoga and then there’s cow urine. Even as the Modi government’s new policy paper reiterates the need to limit patents in the name of public health, it repeatedly argues for plucking “traditional knowledge” out of a multimillennial cultural commons and patenting it.

With this move the B.J.P. is picking up unfinished business from its previous excursion in power, when it led the National Democratic Alliance government between 1998 and 2004. That was the time when the Council of Scientific and Industrial Research and the Center for Research in Cow Science, an outgrowth of Hindu nationalist groups, first tried to patent cow-urine technology in India.

According to the Hindustan Times, over the last decade the Council of Scientific and Industrial Research has spent around $50 million on patent applications, including for using cow urine in health tonics, energy drinks and chocolate. The health ministry’s special department for traditional knowledge — known as the AYUSH department, for Ayurveda, Yoga & Naturopathy, Unani, Siddha and Homoeopathy — was elevated to a full ministry after the B.J.P. won the general election in 2014.

Patenting cow urine is a natural extension of the Hindu right’s obsession with the cow. It makes ideological sense for a nationalist party that rides on a wounded Hindu psyche to claim that Indian science was well ahead of Western science. But this is bad history. A large part of what India claims as its indigenous heritage isn’t exclusively ours: Unani medicine comes from Persia; the origins of homeopathy are German.

The B.J.P.’s nativist, Hindu-pride approach to patents is also bad economics. It unwittingly serves the interests of Big Pharma, and in time this will undercut India’s own pharmaceutical industry, which generates some $15 billion in annual revenues even while producing affordable drugs that benefit the public.

India’s patent laws, currently under consideration as a model in South Africa and Brazil, are a world-class innovation; our cow-urine technology, which has yet to garner much interest abroad, is not. To patent cow urine isn’t just silly. It also endangers a remarkably innovative patent system that has served India’s people and many others around the world so well.