This health care bill Congress is about to pass seems too good to be true. That's because it is.

Naming a piece of legislation is partially a marketing exercise, and the 21st Century Cures Act is a hell of a brand name.

The bill, which passed the House on Wednesday with a strong bipartisan majority and is expected to do the same in the Senate next week, has been described by its Republican sponsor, Michigan Rep. Fred Upton, as “a transformational bill to bring our health infrastructure light years ahead.” The White House agreed, calling it “critically important” and urging the Senate to approve it so that President Obama can sign it before leaving office.

The package includes increased funding for mental health care and the opioid epidemic, two public health issues that have significant public support but have nevertheless stalled in our shitty Congress. There’s also more money in there for the National Institutes of Health and Joe Biden’s “moonshot” to advance cancer research.

At first glance, the bill appears to be a kind of a legislative unicorn: an austerity-obsessed, Republican-controlled House actually agreeing to spend money on Democratic-backed public health initiatives and government institutions.

But the fine print of the 21st Century Cures Act tells a more complicated story.

The measure, which is nearly 1,000 pages long, includes a number of provisions that have some patient advocacy groups and physicians deeply concerned for the safety of their patients—particularly for underserved communities that are already struggling with access to good medical care.

Dr. Reshma Ramachandran, an assistant scientist at the Johns Hopkins Bloomberg School of Public Health, started monitoring the bill back when it was first introduced in 2014. She saw real potential in some of the bill’s major aims, but was also alarmed by some of its provisions “right from the get-go.”

Chief among her concerns was the way the bill tampered with what she viewed as crucial regulations that prevent unsafe drugs from reaching patients.

“We saw a lot of language to expedite approval of new drugs through the FDA, and that sent up a red flag,” she told me.

Right now, in order for a drug or a medical device to get FDA approval, and find its way to patients, it has to go through a pretty rigorous screening process with different standards of evidence through things like randomized clinical trials. The 21st Century Cures Act would change that by speeding up that process and using anecdotal evidence and observational data to clear a drug for approval. This could mean patient feedback that wouldn’t currently be sufficient evidence might be used to help move drugs into the marketplace more quickly.

Supporters of the bill call this change “accelerating” drug development to encourage innovation and competition, but physicians like Ramachandran see it as a gamble that incentivizes rushing drugs to market after weak testing or on anecdotal evidence. “Any kind of experience I have, even with an experimental drug or a drug that might have not gone through the last mile of clinical trials, could be enough for the FDA to give it their stamp of approval,” she said.

This could be a particularly alarming prospect for low-income patients. Currently, patients are sometimes given free samples of medications that doctors receive from drug companies. The practice is controversial because of potential conflicts and influence that comes with pharmaceutical companies pushing their products, but it’s also an imperfect method to help some people, including people in poverty, get treatment that might otherwise be out of reach.

But the free samples are often weighted towards new drugs, and less vetting means less confidence in the medications being distributed, according to Ramachandran.

“The concern I have, especially for underserved populations, is that the things we have in our back pocket—through sample closets or discount cards—would be approved based on a lower standard,” she said. “It’s a bad mix—giving our underserved populations access to potentially unsafe and ineffective drugs.”

Another provision of the bill exempts physicians from disclosing speaking engagements and other relationships with medical companies that could influence their prescribing habits, reversing a current transparency requirement that helps patients stay informed about their physicians’ business interests.

It’s these kinds of concessions to pharmaceutical companies that have Senators like Elizabeth Warren and Bernie Sanders opposing the bill, even as it offers vital funding to public health programs they support.

Warren, in a speech on the Senate floor earlier this week, called the bill a “huge giveaway to giant drug companies” that legalized “fraud.”

“Pushing treatments without scientific evidence that they work is fraud—fraud that can hurt people,” said the Massachusetts Democrat. Defanging the FDA approval process, she added, “undercuts the development of real cures.”

And this is where vulnerable patients may lose the most. In order to secure some short-term funding for overlapping and long-ignored public health crises, Congress may be signing away the legitimacy of the FDA in the process. “It derails the agency that protects our patients from bad drugs and bad devices,” Ramachandran said.