Gene Cavallo, 61, a New Mexico businessman who put his children through college, had always paid his bills promptly and had an excellent credit rating, until he required surgical excision of a melanoma on his shin two years ago. The more than 60 bills generated for the surgery and six months of follow-up visits — arriving sporadically and ranging from 18 cents to $17,000 — came to $110,000; his insurance covered about $70,000.

When various providers asked him to pay the remaining $40,000, he requested itemized bills and balked at some of the “ridiculously inflated prices,” such as $85 for tweezers and $20 for a box of tissues. He argued the bills point by point, and ultimately agreed to pay $25,000.

But during the negotiations some of the debt was sent to collection. Two years later, he no longer answers the daily robocalls from collection agencies and has had a couple of credit cards canceled because his score has fallen. “It was a scary thing to do because I own a business and dabble in real estate, so the ability to borrow has always been important to me. And now I have no ability, I assume, to borrow for any reason.”

Michael S., who declined to give his full name so as to protect his reputation with business clients, had to declare bankruptcy in Wisconsin more than five years ago after a fraught year in which his toddler was evaluated for what proved to be a benign neurological condition that required no treatment: “You’d get bills for several different doctors’ groups and for tests and M.R.I.s and you don’t know what they are. I was having trouble figuring out who we owed what. And then, if it goes to collection, then suddenly they’re saying we need this paid now.”

With medical expenses, unlike most other purchases, you generally don’t know the price the hospital will charge in advance. And the subsequent bills and insurance statements — so-called explanations of benefits — are often layered in obfuscation and pressure tactics.

Consider Chris Sullivan of Pennsylvania, whose $2,770 bill for an echocardiogram offered a “prompt payment” discount of 20 percent if he wrote a check within 21 days — meaning a discount for not asking questions on a bill for a test he was told would be under $300.

Another “explanation of benefits” statement notified Joe Cotugno of New York City that his two-day hospital stay for a hip replacement was billed at $99,469.70 (doctors’ fees not included). Cigna paid $68,420.53 after knocking off some $28,000 and requiring Mr. Cotugno to pay $3,018.41. So, it informed him, “You saved 96 percent.” Huh?