Environmental diseases are illnesses or conditions that can not be linked to genetics or infectious agents such as bacteria or viruses. These types of diseases are very common in industrialized nations and may be due to trauma, exposure to toxins, chemicals or radiation, diet and lifestyle, stress and any form of physical, mental, or emotional abuse.

In the US, many diseases, particularly forms of cancer, are caused by exposure to chemicals and toxins from pollution and industrial cleaning or personal care products. One example is breast cancer that has been linked to aluminum used in deodorant, as well as stomach illnesses from drinking water that contains traces of heavy metals such as copper or lead. Chemical compounds such as carbon monoxide, ammonia, chlorine and fluorine are also linked to many respiratory diseases.

Many diseases that have hereditary origins may also be caused by environmental factors, or may be aggravated by them. One such disease is asthma, which results from constriction or inflammation of the bronchial airways in the lungs. This condition is often present in those with a family history of the illness, but it may also develop over time due to exposure to irritating chemicals, pollutants or allergens. Animal fur and dander are common allergic triggers, along with smoke, pollen and dust mites. Weather variations, such as excessive cold or extreme humidity, may cause asthmatic reactions. Some medications may also be allergic triggers; NSAIDS such as ibuprofen and aspirin are often responsible for asthmatic flare-ups.

Mold and mold spores are also an environmental trigger that can aggravate symptoms of asthma or even cause serious health concerns. Some people may have severe and life-threatening allergic reactions to mold spores. Others may suffer from respiratory, sinus or digestive tract infections, as well as skin infections from direct contact with mold spores. Athlete's foot is a mild form of a skin infection caused by contact with mold and fungi, although the infections can range across the spectrum from mild to life-threatening lung infections. Those with compromised immune systems, such as children, the elderly or HIV / AIDS sufferers, are at special risk for developing infections due to mold.

Mold spores found on grains have been responsible for the death of cattle and humans, due to toxic compounds known as mycotoxins. Excessive or prolonged exposure to certain types of mycotoxins can cause serious neurological problems that may result in death. Fortunately, however, mycotoxins are only produced under certain conditions and death due to exposure is fairly uncommon. There are some mold products that are actually beneficial to humans, such as penicillin.