Although vinegar is not as effective as commercial cleaners, it is a natural disinfectant that can kill bacteria and viruses. Vinegar's disinfecting properties come from the acetic acid that is part of its composition, but this acid also damages some types of surfaces, so it should be used with caution.
Vinegar offers the benefits of being biodegradable, non-toxic and inexpensive, so it's safe enough to be used even by children for cleaning. However, it cannot kill all types of bacteria. For instance, researchers in the United Kingdom found that vinegar kills the flu virus, but it is ineffective against certain types of salmonella.
For general household cleaning and disinfecting, use a 50/50 solution of water to vinegar. Some tougher tasks, such as cleaning mildew or disinfecting porous surfaces, may require a stronger solution or pure vinegar. It is safe to use on most household surfaces; however, vinegar is corrosive to marble due to its acidity. Mixing bleach and vinegar should be avoided as it creates chlorine gas, which is toxic.