Black mold symptoms & dangers

Updated July 20, 2017

Black mould, sometimes known as toxic black mould, can grow on many surfaces within the home. It is very common and tends to grow in damp areas with poor ventilation and moderate temperatures. Exposure to black mould can cause illness with many different symptoms; chronic exposure to black mould can lead to severe illness in some people. You should always try to remove mould and prevent it from reoccurring.


Although anybody can be affected by toxic black mould in the home or in the workplace, for certain people exposure is especially dangerous because they may be more susceptible to it in some way. This may include people with compromised or reduced immune function; for example, those who are ill, the elderly or young children. Pregnant women may also suffer more from the effects of toxic black mould. In addition, black mould may be more harmful to people with asthma or other respiratory illnesses since black mould often affects the lungs and respiratory system.


Mold can cause a variety of symptoms. An unusual amount of symptoms should be further investigated, both by a doctor and by examining the house or building where the affected person spends a lot of time. The most common black mould reactions include respiratory problems, flu-like symptoms, skin rashes, nausea and irritated eyes. Increased susceptibility to colds and common illnesses may also occur; being ill more often than expected may also be a symptom of black mould exposure.


Black mould can cause not only unpleasant short-term symptoms but also much more severe, long-lasting symptoms and illnesses. Allergic reactions to black mould are common and may result in several symptoms all at once; for example, respiratory irritation, coughing, skin rashes and irritated eyes. The presence of mould may also cause asthma attacks in those with the condition, which can be very serious. Memory loss may also occur from long-term mould exposure.

Mold Removal

If black mould is discovered, whether or not any symptoms have been experienced by anyone, it should be removed and its potential causes eradicated. Mold formations, if very severe, should be cleaned and removed by a professional. You can clean up smaller mould formations or the beginning of formations; however, you should wear respiratory protection. You can remove mould using strong cleaning substances such as bleach. To prevent the mould from returning, ensure that all areas are well-ventilated; humidity or dampness is a significant source of mould formation.

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About the Author

Jess Smith has been a writer and editor since 2008. She served as co-editor-in-chief for the "Edinburgh University Science" magazine. Smith holds a Master of Science in neuroscience from the University of Edinburgh.