Mold is not poisonous, but according to Mayo Clinic it can cause mild to severe allergic reactions the symptoms of which are sneezing, congestion, cough, inflammation of the eyes and throat and watering of the eyes. Individuals with asthma may experience more severe symptoms including shortness of breath and in some cases fungal infections of the lungs.
Even general mold allergy symptoms can be cause for concern if they go unchecked for long periods of time. They can damage an individual's quality of life, impair their ability to take part in sports, exercise and other strenuous activity and hamper their ability to breathe and exert themselves in general.
Hypersensitivity pneumonitis is a condition mold exposure and allergic reaction can trigger, especially in those predisposed to afflictions of the lung. According to the United States Centers for Disease Control and Prevention, this condition is mediated by the immune system and can become dangerous if it is left untreated or if it afflicts an otherwise compromised individual.
Sometimes exposure to mold can trigger extremely dangerous asthma attacks in asthma sufferers. These attacks can be life threatening and require immediate medical attention. Those people with asthma should take any and all steps necessary to minimize their contact with mold and with moldy areas of homes or gardens.