Democrats, meanwhile, tried to pin him down on potential cuts to the state- and federally funded Medicaid program that Republicans are considering.

The 64-year-old was a respected heart surgeon who turned into a popular TV pitchman. Now he has his sights on overseeing health insurance for about 150 million Americans enrolled in Medicare, Medicaid or Affordable Care Act coverage.

Oz has hawked everything from supplements to private health insurance plans on his former TV series, ‘’The Dr. Oz Show,‘’ which ran for 13 seasons and helped him amass a fortune.

Oz’s net worth is between $98 million and $332 million, according to an analysis of the disclosure, which lists asset values in ranges but does not give precise dollar figures. His most recent disclosure shows he also holds millions of dollars worth of shares in health insurance, fertility, pharmaceutical and vitamin companies. He has promised to divest from dozens of companies that would pose conflicts for him as the CMS administrator.

In the job, he could wield significant power over most health companies operating in the U.S. because he can make decisions about who and what are covered by Medicare and Medicaid.

Oz’s hearing comes as the Trump administration seeks to finalize leadership posts for the nation’s top health agencies. On Thursday, Senate committees voted to advance the nominations of Marty Makary, poised to lead the Food and Drug Administration, and Jay Bhattacharya, set to helm the National Institutes for Health, for a full Senate vote. The nomination of Dave Weldon to the Centers for Disease Control and Prevention was abruptly withdrawn Thursday.