There's Red Cross-style, by-the-book first aid and then there's advice you get from your mom or next-door-neighbor. Either can become outdated.

"New understanding can change what was once sound medical advice," says Charles Pattavina, MD, chief of emergency medicine at St. Joseph's Hospital in Bangor, Maine.

Much of the time, hand-me-down safety tips are harmless. But in some situations, first aid mistakes and old-think can dangerously delay treatment, slow healing or cause complications, says Pattavina, a spokesperson for the American College of Emergency Physicians.

When giving first aid, Pattavina says, "Do no harm." Here are 10 mistakes to avoid.

Putting butter on a burn

Why it’s a mistake: A layer of grease on a burn increases the risk of infection, according to the Red Cross.

The better way: Don't put anything on a burn except cool (not ice-cold) water. Cover it with a sterile dressing. Get immediate medical treatment for a severe burn — one that damages deep layers of skin, covers a large area or blisters.

Related: Avoiding Campfire Burns

Cooling a fever with an alcohol rubdown

Why it’s a mistake: As alcohol evaporates, skin feels cooler, but internal body temperature doesn’t necessarily drop. An alcohol rub may be harmful, especially for children, because alcohol is absorbed by skin and is toxic to the nervous system, according to the University of Rochester Medical Center.

The better way: If you have a fever of 102 F or higher, rest, drink plenty of fluids and take a fever-reducing medication such as acetaminophen or ibuprofen. See your doctor if your fever lasts more than three days, advises the Mayo Clinic. Call the pediatrician if your child has a fever over 104 F or runs a temperature for more than three days. A baby under 3 months should be seen by a doctor for a fever above 100.4.

heating pad man

Trying to thaw a frostbitten body part with hot water

Why it’s a mistake: Hot water (108 F or higher) can further damage injured skin. So can sitting too close to a fire or heater, according to the University of Michigan Health System.

The better way: Put the body part in warm water (100.4 F to 105 F) or use a heating pad set on low, advises University of Michigan Health System. Don't do either if there's any chance the body part will be exposed to the cold and freeze again. Never rub or massage frozen skin. (Photo: Image Point Fr/Shutterstock)

Related: Stay Safe in Crazy Cold Weather

Using a tourniquet to stop an extremity from bleeding

Why it’s a mistake: Depending on where you tie it, a tourniquet can stop blood flow to an entire foot, leg, hand or arm, causing permanent damage. The Red Cross advises using a tourniquet only as a last resort.

The better way: Apply pressure to the wound with a padding of sterile or clean cloth. If the wound is deep or has dirt or grit in it, get to a doctor or urgent care center. Call 911 if bleeding seems dangerously heavy.

Related: Emergency! Should You Drive to the Hospital or Call an Ambulance?

Scrubbing a knocked-out tooth before trying to put it back in the socket

missing tooth manWhy it’s a mistake: The friction will remove delicate tissue from the tooth that's needed to help it reattach.

The better way: If the tooth is dirty, hold it by the chewing surface (not the sides) and gently rinse with water. Head to a dentist, or even better, an endodontist. Keep the tooth moist by placing it in a clean container of milk or use an emergency tooth preservation kit. If you're an adult, you can tuck the tooth inside your cheek, says the American Association of Endodontists. (Photo: www.BillionPhotos.com/Shutterstock)

Giving ipecac syrup to cause vomiting if someone has swallowed poison

Why it’s a mistake: A caustic or toxic substance may cause more damage on the way up.

The better way: If the person has no symptoms, call the poison control center (800-222-1222) and tell them what was swallowed. You'll be advised what to do. If the person is drowsy or agitated, has a seizure or is struggling to breathe, call 911. Give the packaging or container if you have it to the emergency responders, advises the Mayo Clinic.

Tilting your head back to stop a nosebleed

Why it’s a mistake: It won't stop the bleeding and blood may drain down your throat and cause you to vomit.

The better way: Tilt your head forward. Pinch the bridge of your nose with your thumb and forefinger. Slide the "pinch" down to where bone meets cartilage. Hold firmly for five minutes. Repeat if the bleeding doesn't stop. If bleeding continues after two tries, Harvard Medical School advises seeing a doctor.

eye doctor patient

Rubbing your eye to get something out of it

Why it’s a mistake: Rubbing could scratch your cornea.

The better way: Wash your hands and look in a mirror. If you can see the object, you may be able to remove it by touching it with a cotton swab or the corner of a clean cloth. If that doesn't work or you can't see it, blink a few times. Your tears may wash it away. If they don't, you may be able to flush out the object with lukewarm water or eye drops. Have a doctor look at your eye if it's red, painful or sensitive to light, or if you can't get the object out. (Photo: massimofusaro/Shutterstock)

Related: 10 Foods to Eat for Eye Health

Putting something in a person's mouth so he won't swallow his tongue during a seizure

Why it’s a mistake: It's unnecessary. The Epilepsy Foundation says, "A person can't swallow their tongue during a seizure."

The better way: Turn the person having a seizure on her side and tilt her head so her mouth points downward to keep the airway free of saliva. If she's not lying down, help her sit down and protect her head should she fall over. Do not try to restrain her.

Putting first aid ointment on a cut or scrape

Why it’s a mistake: A moist wound is vulnerable to infection, says the Red Cross.

The better way: Clean the wound with soap and cool water — no antiseptics or disinfectants — and cover it with a clean, dry bandage . The Red Cross suggests a looser bandage at night so air can get to the wound.

Dianne Lange is a Lake Tahoe-based freelance writer specializing in health and travel. She is the author of four books on cancer and a former editor at SELF, Health, Natural Health and Prevention. Her work has appeared on websites such as RealAge.com, SymptomFind.com, WebMD and Everyday Health.