Lemons add color and flavor to food and provide a healthy dose of vitamin C. One-half cup of lemon pulp and juice supplies 90 percent of the recommended daily amount of vitamin C. Acidic lemons have a refreshing sourness most people cut with sugar or honey. If you use it in cleaning, lemon juice can cut through grease, so you might reason that it would also cut through bodily mucus. But little evidence exists to support the idea that ingesting lemons or drinking lemon juice will decrease the amount of mucus you produce, or relieve the congestion of a cold or sinus infection.
Colds, allergies and sinus infections can lead to a stuffy nose and sinuses clogged with thick mucus. Tea with lemon, hot lemonade or honey and lemon are common home remedies that can help ease congestion. But their positive effect might derive from the liquids more than from the inclusion of lemon. Drinking more liquids helps to thin mucus and unclog sinuses. The high vitamin C content of lemons could reduce the duration of your cold by 8 to 14 percent, according to the Linus Pauling Institute.
Cystic fibrosis patients produce too much mucus, which clogs the lungs and digestive system. There is currently no cure for cystic fibrosis. Treatments aim to manage symptoms. In addition to medication and physical therapy, the University of Maryland Medical Center recommends that cystic fibrosis patients consume more foods that decrease mucus production, including lemons. Lemons alone, however, are unlikely to have much effect on the disease.
Your nasal passages aren't the only area in your body that produces mucus. Your stomach produces mucus, which serves to line and protect your stomach from harmful substances. Substances that irritate or thin this gastric mucus can lead to injury or ulcers. Researchers at Sao Paolo State University reported in the August 2009 issue of "Chemico-biological Interactions" that introducing limonene, a phytochemical found in lemons, to the stomach prompted the stomach to produce more mucus, and protected the stomach from damage from nonsteroidal anti-inflammatories, a common cause of ulcers. Limonene is often used as a flavoring agent.
If you enjoy lemons, help yourself to lemonade, lemon water and honey and lemon for a cough or sore throat. Some people might not tolerate the acid in lemons if they consume a lot of them, and the high sugar content of many lemon beverages can be a concern for some.