A noxa is any component of the natural context, with the ability to cause some damage to the person who rubs against it. The noxas can be classified into biological, physical, chemical, social and psychic noxas. Within the group of biological noxae we find all those viruses, bacteria or parasites that, due to lack or excess, are capable of causing negative affections for people, likewise, it is important to highlight that there are some microbes or bacteria that are beneficial for the individual, but if they are scarce or reduced they can also generate diseases in people.

Within the group of physical and chemical noxa, all the elements derived from physics and chemistry are included. An example of a chemical noxa is when a food that is in poor condition is eaten, or when breathing toxic products; An example of physical harm would be exposing oneself too much to the sun’s rays, receiving a blow, sudden changes in temperature, etc.

Within the group of social and psychic noxas are included all the external elements in which people rarely have control, but which can also cause different diseases, among the external elements we can mention environmental pollution, stress, the economic situation and country politics, lack of employment, insecurity, racism, etc. For example, people can rarely exercise control over the economic and political crisis in their country, but the simple existence of it causes anxiety, stress, bad mood, insomnia, etc. in the individual.