A cough usually occurs in response to viral damage to air passageways. Even after the infection is gone, tissues may take a while to heal; the resulting cough can linger for weeks or even months. In most cases, medication won't make the airways heal quicker. To speed healing, avoid exposure to a very dry environment. In the winter, keep indoor air moist by running a humidifier.
Also, try not to cough harshly. Calmer coughs allow for quicker healing. But avoid cough suppressants, because they generally are not effective at this stage. Antihistamines can also dry out the airways. If possible, stay inside during very cold weather—a strong trigger for coughing—and minimize exposure to other infections, which could cause further damage. Most important, be patient. The body has a natural healing process—let it run its course.
When you have a cough, a few things can inhibit healing. Dairy and other mucus-producing foods can slow the healing process. And if you're prone to respiratory allergies, they can exacerbate a cough, too. Herbs that help heal coughs caused by viruses include lomatium (Lomatium dissectum), gumweed (Grindelia camporum), and licorice root (Glycyrrhiza glabra) extract. The dose in tincture form is 30 drops, three times per day. For an especially persistent cough, try wild cherry bark (Prunus serotina).
For dry coughs accompanied by thick mucus that won't clear out, take black horehound (Ballota nigra), which will help bring up more phlegm. For a moist cough, add elecampane (Inula helenium), which will help dry up the excess mucus. Finally, yerba santa (Eriodictyon californicum) is well known for helping sufferers get over chronic coughs after a bout of flu.
In the practice of Chinese medicine, several herbs promote healing by helping to thin mucus and calm the coughing reflex. Luo han guo (Momordica grosvenori) is commonly available as a tea in natural product stores. Brew one tea bag, and drink three times daily. Bei mu (Fritillaria spp) contains alkaloids that serve as reliable cough suppressants. Look for it in syrup form and take according to directions on the bottle. Pi pa ye (Eriobotrya japonica), or loquat leaves, can help alleviate coughs. The combination of pi pa ye and bei mu is common in Chinese herbal cough syrups.
Keep in mind that these herbs won't inhibit infections, but they can help with symptoms. Given time, and with relief from herbal cough remedies, the disorder should clear up. However, if the condition persists or worsens, a visit to your doctor is in order.