Chronic diseases are often associated with misguided processes within the body — normal and necessary operations that have gone awry and are creating complications that can set the stage for illness. And many herbs possess the exact constituents that are missing in someone with these problems.

A common denominator in many chronic diseases is inflammation, which is the body's natural reaction to an injury or invading pathogen and is a key component of the healing process. But prolonged or chronic inflammation leads to a cycle of destruction and healing that seems to perpetuate the development of disease by interfering with immune function.

For example, people with ulcerative colitis, a chronic inflammatory condition of the colon, are at a greater-than-average risk for colon cancer. And having a chronic inflammatory lung condition like asthma seems to increase your risk of lung cancer, even if you're not a smoker. Many herbs are natural anti-inflammatories, meaning they can help reduce the type of ongoing inflammation that's been associated with so many chronic diseases.

Many chronic diseases are also associated with oxidation, which is a chemical reaction that occurs naturally throughout your body and in the outside world (it's what turns metal rusty and a slice of apple brown). Through oxidation, an oxidizing agent removes electrons from another substance; this reaction can produce molecules called free radicals, which can damage cells. In a healthy body, free radicals are kept in check by molecules called antioxidants. If there aren't enough antioxidants around, the cells can sustain oxidative damage, also known as oxidative stress, which is known to play a role in many chronic diseases.

Many herbs are powerful antioxidants, meaning they can blunt the damaging and disease-producing effects of free radicals within the body. For example, research has shown that people who consume lots of antioxidantrich plants have lower rates of cancer and heart disease.