While there can be some health benefits to using a nasal rinses (also called nasal irrigation) or mouthwash, there is no scientific evidence that rinsing with vinegar can prevent or treat COVID-19. COVID-19 is caused by coronaviruses with an outer lipid (fat) membrane, so washing hands with soap and using a hand sanitizer with at least 60-70% alcohol can be effective against this type of virus. Wearing a mask or face covering can help prevent viral particles from entering or exiting through the mouth and nose.

Nasal rinses and mouthwashes are often used in an attempt to help clean nasal and oral cavities. Common nasal rinses include sterile water with salt (called saline solution when it contains 0.9% salt, similar to the sodium content in body fluids) or baking soda.

Vinegar, a mixture of acetic acid and water, is mildly acidic. Different types of vinegar can contain other substances for flavor and color. Medical professionals advise caution when rinsing with substances that could irritate sensitive membranes in the nose, mouth and throat. Rinses should not be swallowed. It is recommended that people avoid using rinses if they have recent facial/throat surgeries, ear infections, blocked sinus/nasal or ear passages, swallowing disorders, persistent canker sores, or bleeding gums. Painful rinses should be stopped, and people should consult their doctor or dentist if irritation persists.

Nasal and oral rinsing is occasionally used to help expel excess mucus, if a minor illness or infection has caused the body to overproduce mucus in a way that is uncomfortable or makes breathing feel difficult. Sputum is a thick mucus that is sometimes called phlegm and is a natural part of the body's defenses. Sputum keeps the thin tissues of the respiratory tract moist and helps prevent small foreign particles from entering. White or clear sputum can be normal in a healthy person, but coughing up an excess amount can be an indicator of allergies, infection, or respiratory conditions including asthma and chronic obstructive pulmonary disease (COPD). Sputum of a different color (e.g. green, yellow) can also indicate infection or disease, including sputum colored with blood. People should consult their doctor if they are coughing up an excess amount of sputum.

Over-rinsing or rinsing with harsh substances can cause harm rather than health benefits. Nasal rinses and mouthwashes should follow medical and dental guidance. COVID-19 prevention and treatment methods should follow public health and medical guidance

Many people are seeking ways to prevent and cure COVID-19 infection during the current global pandemic. Some people are trying home remedies, despite the lack of scientific evidence for several of the remedies. Some of these home remedies include nasal and oral rinses with different substances. Known ways of preventing viral particles from entering the nose and mouth include keeping physical distance, wearing a mask, practicing good hand hygiene and trying not to touch the face. Research is continuing to study effective ways of preventing viral particles from entering or taking hold in our nose, mouth, throat, and lungs. COVID-19 vaccination can protect people from serious disease symptoms, hospitalization, and death when viral particles do manage to enter the body.