Disinfectants: A guide to killing germs the right way | MNN

From drug-resistant bacteria to flu outbreaks and COVID-19, health scares seem to dominate the news these days. In response, you may go searching for products that claim to eradicate bacteria, viruses and other germs.

Not all of these disinfectants are effective against every type of bacteria or bug, however. And although we may think these products are keeping us healthy, the truth is some may be harmful to both our health and the environment.

To help you choose the right disinfectant, we’ve provided some pros and cons below for a variety of germ-busting agents. We’ve also added some notes about the novel coronavirus SARS-CoV-2, which causes the disease known as COVID-19.

This coronavirus seems to spread most commonly from person to person via respiratory droplets, according to the U.S. Centers for Disease Control and Prevention (CDC), usually between people who are within about 6 feet (1.8 meters) of each other. Transmission of the virus from contaminated surfaces has not yet been documented, the CDC notes, but current evidence does suggest the virus can remain viable “for hours to days on surfaces made from a variety of materials.”

To disinfect surfaces, the CDC recommends a household bleach or alcohol solution (see below for details), and points to a list of disinfectant products registered by the U.S. Environmental Protection Agency (EPA) that have qualified for use against the novel coronavirus. Washing with soap or water is the best way to rid the virus from your hands, the agency adds, but if soap and water aren’t available, an alcohol-based hand sanitizer with at least 60% alcohol may be used.


Bleach is a relatively cheap and highly effective disinfectant. It kills some of the most dangerous bacteria, including staphylococcus, streptococcus, E. coli and salmonella — as well as many viruses, including the flu and the common cold. It should also work on the novel coronavirus, according to the CDC, which notes that “unexpired household bleach will be effective against coronaviruses when properly diluted.”

In its guidance for COVID-19, the CDC advises using a bleach solution with 5 tablespoons (1/3 cup) bleach per gallon of water, or 4 teaspoons bleach per quart of water, and following manufacturer’s instructions for application and ventilation.

While bleach can be an important disinfectant in some situations, though, it’s also a potential hazard to human health, capable of not only irritating sensitive tissue in the eyes, skin, mouth and throat, but also contributing to long-term respiratory problems like asthma. Bleach can also be hazardous to pets, wildlife and ecological health. There are some safer alternatives in disinfecting wipes and cleaning sprays, although these eco-friendly choices may not be as effective in killing bacteria and viruses. Also note that both bleach and bleach alternatives are intended to disinfect surfaces, and should not be used on the skin, and that bleach should never be combined with ammonia or ammonia-based cleaners.

Soap and water

man washing hands
Don’t just run your hands quickly under the water. (Photo: fizkes/Shutterstock)

Regular soap and water clean germs away rather than killing them, but that’s still a key step in reducing infection, the CDC points out. Washing your hands with soap and water is one of the main recommendations for limiting the spread of the novel coronavirus, since it seems to spread primarily from person to person via respiratory droplets, which are often found on our hands and easily transferred to our faces.

Store shelves are also filled with products that boast antimicrobial properties, including antibacterial soap. There is a common misconception, however, that antibacterial soap is effective in eradicating all germs. Although antibacterial soap may kill some bacteria, there is little evidence that it’s more effective than regular soap, and it offers no additional protection from viruses.

In fact, many health experts advise against using antibacterial products, as many contain a potentially harmful ingredient called triclosan, which some research suggests is an endocrine disrupter. Moreover, overuse of these products may contribute to antibiotic resistance and the rise of so-called superbugs.

Ammonia-based cleaners

Although it may be a more environmentally friendly cleaning solution than many other products, ammonia is not registered as a disinfectant by the EPA. Ammonia might kill salmonella and E. coli, but it is not an effective defense against dangerous staphylococcus bacteria. And remember never to mix ammonia with bleach.

Alcohol-based hand sanitizers

bottle of hand sanitizer with pump
Alcohol-based hand sanitizers can work against many bacteria and some viruses. (Photo: Singkham/Shutterstock)

Alcohol has long been used as an antiseptic. Ethyl alcohol in particular is effective against a wide range of bacteria, and also some viruses, namely those known as “enveloped viruses.” These viruses — including influenza and coronaviruses — are enveloped in a lipid membrane that can be disrupted by alcohol and other disinfectants, thus inactivating the virus. Alcohol may not be helpful, however, against viruses that lack this envelope, such as norovirus.

For disinfecting surfaces, the CDC advises using an alcohol solution with at least 70% alcohol. For hand sanitizers, it suggests using one with at least 60% alcohol, although it notes washing your hands with soap and water is preferable. The U.S. Food and Drug Administration (FDA) has warned the makers of some hand sanitizers against claiming their products can prevent infections like the flu, citing inadequate evidence. If you buy hand sanitizer, avoid products that contain triclosan. As an alternative to buying it, you could also make your own hand sanitizer at home.


Vinegar can be used as a safer bleach alternative for some applications, such as cleaning, and research has shown it can be affective against some bacteria and viruses, including the flu. It is also biodegradable. Vinegar is not a registered disinfectant, however, and does not kill dangerous bacteria like staphylococcus.

Hydrogen peroxide

Hydrogen peroxide has antimicrobial properties and can be an effective household cleaner. It is also highly biodegradable. However, concentrated hydrogen peroxide is extremely dangerous and should only be used as a disinfectant at concentrations lower than 3%.

Baking soda

Although baking soda is often used a household cleaner, it is ineffective against most bacteria, including salmonella, E. coli. and staphylococcus. If you suspect there has been a contamination of any of these bacteria, ditch the baking soda in favor of a product registered as a disinfectant by the EPA.

Tea tree oil

Tea tree oil is a natural, biodegradable antiseptic that can be useful for treating minor cuts and wounds. It may not be strong enough to kill viruses and more powerful bacteria, though.

Editor’s note: This article has been updated with new information since it was originally published in March 2013.

Disinfectants: A guide to killing germs the right way

Here’s a breakdown of how each disinfectant kills specific types of germs.

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