Lidocaine ointment is a topical numbing medication used to relieve pain from minor burns, sunburn, skin abrasions, insect bites, and irritation of the mouth and throat. The standard formulation contains 5% lidocaine, which temporarily blocks nerve signals in the area where it’s applied, making it one of the most widely used over-the-counter and prescription topical pain relievers.
How Lidocaine Ointment Works
Lidocaine belongs to a class of drugs called local anesthetics. It works by blocking sodium channels on nerve cells, which are the tiny gates that nerves use to send pain signals to the brain. When you apply the ointment to skin or a mucous membrane, lidocaine molecules slip into the inner pore of these channels and physically prevent them from firing. The result is a loss of sensation in that specific area, without affecting the rest of your body.
This blocking effect is “use-dependent,” meaning nerves that are actively firing pain signals are actually more susceptible to being shut down by the drug. That’s why lidocaine is especially effective on irritated or painful tissue. Once lidocaine binds to a nerve’s sodium channel, it’s slow to let go, which is what gives the ointment a sustained numbing effect rather than a fleeting one.
Common Uses for Skin
The most familiar use of lidocaine ointment is for everyday skin injuries and irritations. It’s approved for temporary pain relief from minor burns (including sunburn), scrapes and abrasions, and insect bites. You apply a thin layer directly to the affected area, and most people start feeling numbness within 30 to 60 minutes.
Some people also use lidocaine ointment before minor cosmetic procedures like waxing, tattooing, or microneedling. In clinical settings, healthcare providers may apply it before inserting an IV or performing a skin biopsy. For these pre-procedure uses, the cream is sometimes covered with an occlusive dressing to help it absorb more completely into the skin.
Mouth and Throat Pain
Lidocaine ointment is specifically approved for numbing the mucous membranes of the mouth and throat. This makes it useful for mouth sores, canker sores, sore throats, and gum irritation. In dental offices, it’s routinely applied before injections to reduce the sting of the needle.
For mouth pain, the ointment is placed on the sore area, swished around until the pain subsides, and then spit out. For sore throats, it can be gargled and swallowed. Because it numbs the tissues involved in swallowing, you should avoid eating for at least an hour after using it in your mouth or throat, and skip chewing gum while the numbness is active. Using the smallest amount that relieves your pain helps reduce the risk of side effects.
Lidocaine viscous solutions should not be used for teething pain in infants or children under 3, as serious side effects and even deaths have been reported in this age group.
Rectal and Hemorrhoid Relief
Lidocaine is a common ingredient in rectal creams and gels used for hemorrhoid pain, anal fissures, and general anorectal itching. These products numb the irritated tissue and, when combined with a steroid like hydrocortisone, also reduce inflammation. The combination works on two fronts: lidocaine handles the pain and itching, while the steroid calms swelling.
Rectal formulations should only be applied to the affected area, not to healthy surrounding skin or over large areas. Wash your hands before and after application, and follow the prescribed schedule rather than reapplying whenever discomfort returns.
How to Apply It Safely
Apply a thin layer of lidocaine ointment only to the area that hurts. More ointment does not mean faster or stronger relief. It does mean more lidocaine gets absorbed into your bloodstream, which increases the chance of side effects. Studies on similar topical anesthetics show that thinner applications may produce less complete or shorter-lasting numbness, so a moderate, even layer is the goal.
If you’re covering the ointment with a bandage or dressing to keep it in place, be aware that occlusion increases absorption. This is fine for small areas under medical guidance, but covering large sections of skin with lidocaine under a wrap raises the risk of systemic toxicity. Avoid applying heat (heating pads, hot water bottles) to treated skin, and don’t scratch, rub, or expose the numb area to extreme temperatures. Because you can’t feel the treated skin normally, you could injure it without realizing.
With children, keep the ointment and any dressings out of reach. A secondary covering over the application site can prevent a child from pulling off a bandage and accidentally ingesting the medication.
Side Effects and Warning Signs
Most people experience nothing more than mild redness or irritation at the application site. Allergic reactions are uncommon but possible, and they look like a rash, hives, or worsening redness and swelling.
The more serious concern is systemic toxicity, which happens when too much lidocaine enters the bloodstream. This can occur from applying too much ointment, applying it to broken skin (which absorbs faster than intact skin), or covering large areas. Early warning signs include ringing in the ears, numbness around the lips, dizziness, and confusion. In severe cases, it can progress to seizures or heart rhythm problems. Central nervous system symptoms typically appear before cardiac ones, so those early warning signs are important to recognize.
Lidocaine can also, in rare cases, cause a condition called methemoglobinemia, where the blood’s ability to carry oxygen is reduced. Symptoms include bluish discoloration of the skin, lips, or nail beds, along with fatigue and shortness of breath. This risk is higher when lidocaine is combined with other local anesthetics or used in very large quantities.
Who Should Be Cautious
People with liver disease process lidocaine more slowly, which raises the risk of buildup in the bloodstream even at normal doses. The same applies to anyone taking medications that affect liver enzymes, as these can slow lidocaine metabolism. If you have a known sensitivity to any local anesthetic (the “-caine” family of drugs), avoid lidocaine ointment entirely.
Pregnant or breastfeeding individuals should use lidocaine ointment only when clearly needed and on the smallest area possible. While topical application results in far less systemic absorption than an injection, the drug does cross into breast milk in small amounts.