When you’re admitted to a hospital, you expect your health to improve. But that’s often not what happens: It has been estimated that up to 440,000 Americans die each year after experiencing a hospital-­based medical mistake. That makes those errors the third-leading cause of death in the U.S., behind heart disease and cancer.

What’s more, every year an estimated 722,000 people in the U.S. develop infections during a hospital stay, and about 75,000 die, according to the Centers for Disease Control and Prevention.

Whether a death is due to a patient being given the wrong drug or developing an infection because a doctor failed to wash his or her hands, many are preventable. Here’s what you need to know about five all-too-common medical mistakes:

1. Falls

Falls may not seem like medical mistakes, but they often are. That's because there are a number of steps hospitals can and should take to reduce the risk of the mishaps. In fact, about a million hospitalized Americans fall each year, and at least a third of those accidents could be prevented, according to the federal Agency for Healthcare Research and Quality (AHRQ). And that's important: those falls can not only cause broken bones or internal bleeding, but extend your hospital stay, increasing the chance for more things to go wrong.

Protect yourself. On admittance, make sure the staff assesses your fall risk. “They should also ask whether you’ve fallen in the last few months, and if so, how many times and what the circumstances were,” says nursing consultant Patricia Quigley, Ph.D., former associate director of the Patient Safety Center of Inquiry at the James A. Haley Veterans’ Hospital in Tampa, Fla. “Did you just trip over your dog, or did you fall while in the bathroom?” Make staff aware of all of the drugs you take, too, because some, such as anti­depressants, can make you more fall-prone. If you are at high risk, ask the staff to take protective steps by, for example, moving IV poles out of your path to the bathroom and providing a cane or walker. If you need help getting into and out of bed, always ask for assistance.

Use our Ratings to compare hospitals in your area on infections and other measures and read our special investigation, "How Your Hospital Can Make You Sick."

2. Antibiotic Misuse

More than half of all hospital patients get antibiotics—and up to 50 percent of the time they’re not needed or patients receive the wrong one, according to the CDC. Overuse of those drugs can breed bacteria that are resistant "superbugs," bacteria that are resistant to several antibiotics, making infections hard to treat. And antibiotics can kill off good bacteria that normally live in your gut, allowing harmful bacteria to run rampant. That can predispose you to a dangerous infection now prevalent in hospitals: clostridium difficile, or C. diff. At least 250,000 people develop C. diff infections linked to antibiotic use each year, and 14,000 die.

Protect yourself. If your doctor wants to give you an antibiotic, ask him or her why. When physicians suspect an infection, they should do a rapid culture, if possible, to quickly pinpoint the possible bacteria so that they can prescribe the most effective antibiotic at the lowest dose. Read our special investigation, "The Rise of Superbugs."

3. Medication Mix-Ups

Drug errors or drug-related injuries are one of the most serious medical mistakes that can happen in hospitals, occurring in about half of surgeries. That often happens when a patient gets the wrong dose, according to a small Harvard study published online this past October. Overall, an estimated 1,000 preventable medication errors occur in hospitals each day.

“There are many opportunities for a medication order to go wrong—it goes from a physician, to a pharmacist, then to a nurse to administer it—and a mistake can happen somewhere along that chain,” says Tejal Gandhi, M.D., M.P.H., president and CEO of the National Patient Safety Foundation. Read about how to prevent drug errors in the pharmacy.

Protect yourself. Make sure the hospital staff knows about every medicine you take, including over-the-counter drugs and dietary supplements because they can inter­fere with prescription drugs. When the doctor prescribes medication, you or your companion should write down what each drug is, what it’s for, how often you need to take it, and in what dose. When the nurse administers a medication, verify that it’s the proper drug and dose.  

4. Too Much Bed Rest

Lying in bed is often unavoidable in the hospital, especially if you’re very ill. But it’s quite important to get moving as soon as you are able to do so, because research now shows that walking helps hospital patients to recover faster and leave the hospital sooner. Lying still while hospitalized can also weaken you, making you prone to falls even months later, according to a 2014 Johns Hopkins University study.

“Often, patients are supposed to get out of their bed at least two to three times a day, but it’s often challenging for nurses to always be available because they’re so busy caring for other patients,” Gandhi says.

Protect yourself. Even if you haven’t yet been cleared to get up and walk, you can still try to move while lying in bed: Make circles with your ankles, or tighten and relax your fists. If you feel too weak to walk or you are unsteady on your feet, ask for physical therapy. And don’t hesitate to remind the staff that you need that therapy. “If your care plan calls for getting out of bed three times a day, make sure you’re ringing that bell to ask that a nurse come to help you,” Gandhi says.

Read our Special Investigation, "What You Don't Know About Your Doctor Could Hurt You."

5. Chaotic Discharge

For some of the most common conditions treated in the hospital, as many as one in five hospital patients is readmitted within 30 days of discharge, according to AHRQ. Though sometimes that is unavoidable, often it’s because of an infection that only showed up when a patient got home or because he was discharged before he was ready and needed more treatment.

Protect yourself. Consumer Reports’ research has found that hospitals that do a good job of giving patients discharge instructions tend to have lower re­admission rates. You, or a friend or family member, should meet with a discharge planner at least a day before you’re scheduled to leave. Ask for a clear, written summary of what you should do when you’re home, including how to care for surgical wounds; any diet and activity restrictions; a medication list; copies of all test results; and a scheduled follow-up appointment. You should also ask when to seek immediate care and who to contact in that instance. Read more about how to prevent hospital readmissions and other medical mistakes.