Medical Articles
What Happens If You Leave Mold Untreated?
13.09.2026
In Japan, mold tends to grow during the humid months of the year. In hot and humid countries like the Philippines, however, mold can be a problem throughout the year.
There are tens of thousands of species of mold. Most are harmless, but some can be harmful to human health. Mold growth is actually quite simple. Mold spores are constantly floating in the air. When they settle on surfaces such as walls, they absorb nutrients and use moisture in the air to grow and multiply. As mold grows, it releases tiny spores that are too small to see with the naked eye. We can inhale these spores as we breathe. Healthy people may not experience any problems, but babies, older adults, and people with weakened immune systems should be especially careful. Increased exposure to mold spores can worsen symptoms of conditions such as asthma, atopic dermatitis, and allergic rhinitis.
Mold is more likely to grow when five conditions are present: temperature, moisture, nutrients such as dirt, oxygen, and time. Common places where mold tends to develop include storage areas, bathrooms and other wet areas, and the inside of air conditioners. The most important way to prevent mold is to control humidity. Mold growth is greatly reduced when humidity is kept below 60%. Even opening windows for a short time or using an exhaust fan can help improve ventilation. If opening windows is difficult, a dehumidifier or the dehumidifying function of an air conditioner can also be effective.
Dust and fibers can provide nutrients for mold, so regular cleaning is another effective way to prevent mold growth. When arranging furniture, leaving a few centimeters of space between the furniture and the wall allows air to circulate and can help prevent condensation and mold. Another thing to be aware of is indoor plants and drying laundry indoors. Moisture can evaporate from plant soil and wet laundry, increasing the humidity inside your home. Combining good ventilation with dehumidification can help keep indoor humidity under control.
Mold is often something we think we can simply clean up after it appears. However, when it comes to protecting your health, it is better to focus on preventing mold from growing in the first place rather than dealing with it after it appears. With a few simple steps to control moisture, you can help keep your home comfortable, clean, and healthy.
Author Bio
Dr. Eiji Shimada
Oriental Wellcare Group Founder
Board-certified radiologist. He manages one of Japan’s largest independent teleradiology service companies, receiving more than 10,000 imaging interpretation requests per month from over 250 hospitals nationwide. He also has a track record as a pioneer of home healthcare in Japan, having founded and managed one of the country’s largest medical corporations specializing in home-based medical care.
In November 2014, he founded Oriental Wellcare Group. Today, the group operates a broad network of medical institutions across three countries: the Philippines, Malaysia, and the United States. He is dedicated to creating healthcare environments where Japanese residents overseas, including those living in the Philippines, can receive advanced medical care with peace of mind.