Many people like to steep Malva nut (Pang Da Hai) in water to protect their throats. Some treat it as a specific remedy for hoarseness, and even consume it as a health beverage over the long term. This is highly incorrect. Malva nut also has its drawbacks.
Traditional Chinese Medicine (TCM) considers Malva nut to be cold in nature and sweet in flavor, affecting the Lung and Large Intestment meridians. It has two main functions: one is to soothe the throat and restore the voice, being particularly effective at clearing and lubricating the throat. It can be used for throat swelling, pain, hoarseness, or loss of voice from any cause. The other is to moisten the bowels and relieve constipation, used for conditions like dry-heat constipation, headaches, and red eyes. If it is necessary to take Malva nut, 2-4 nuts can be used alone or in combination with other Chinese herbs such as Licorice, Scrophularia, and Honeysuckle. It can be decocted or steeped in boiling water. Although Malva nut is beneficial, it must be used correctly and appropriately. When Malva nut comes into contact with water, it expands into a sponge-like state, reaching 3 to 5 times its original volume. A common counterfeit, the round Sterculia lychnophora, also expands in water but more slowly, only reaching twice its original volume.
Malva nut is one of the traditional Chinese herbs most susceptible to contamination by aflatoxin, which is a potent carcinogen. Before use, inspect its appearance, smell it, and then break open the two cotyledons to check for mold or pests. Any that are moldy or infested must be discarded.
Malva nut is cold and sweet in flavor. It is not suitable for individuals with a weak or cold spleen and stomach, as it can easily cause diarrhea and damage vital energy (Yuan Qi).
Malva nut should only be used for medicinal purposes, and it should be used "according to the specific condition and discontinued once it proves effective." It should not be consumed as a health beverage or tea, and women should use it with caution during their menstrual period.
Hoarseness caused by vocal cord nodules, polyps, incomplete vocal cord closure, or excessive stimulation from smoking and alcohol will not be relieved by Malva nut.
Furthermore, Malva nut contains galactose and galacturonic acid, so it should be used with caution by diabetic patients. It also has a blood pressure-lowering effect, so individuals with low blood pressure should also be cautious about long-term use. Allergic reactions have also been reported.