Acetaminophen can increase the risk of asthma.

  Asthma in the US has risen by 75% in the last 3 decades. Some experts think that the increasing use of acetaminophen may be partly responsible.

  This is based on several studies showing a positive association with acetaminophen use and asthma. There are a couple of proposed theories of how acetaminophen might increase the risk of asthma.

  Acetaminophen reduces glutathione levels in the lungs. It's thought that glutathione helps to protect the lungs from oxidative stress. In fact, there's some evidence that people with asthma have lower glutathione levels than healthy people.