The Medicinal Value of the Potato (Maling Shu / Tudou)
The potato (Solanum tuberosum) is the tuber of a plant in the nightshade family (Solanaceae). It is a common food, and almost everyone has eaten potatoes. We know potatoes have high nutritional value, but few realize they also have considerable medicinal value; when used properly, potatoes can treat many common minor ailments.
However, sprouted potatoes have no medicinal value and are in fact somewhat toxic. Animals that ingest certain alkaloids (free solanine) present in sprouted potatoes develop a solanine toxic reaction, which can worsen colonic tissue injury and trigger inflammatory bowel disease in interleukin-10 gene-deficient mice. Therefore, in daily life we should not use sprouted potatoes (especially their green parts), and when using potatoes medicinally, sprouted potatoes should likewise be avoided.
Traditional TCM holds that the potato harmonizes the stomach and fortifies the middle, resolves toxicity and reduces swelling, and is used for stomach pain, mumps (zhaxia), carbuncles and swellings, eczema, and burns and scalds.
Modern pharmacological research has confirmed that the aqueous dialysate of potato inhibits the mutagenic action of certain carcinogens on Salmonella typhimurium. In plant lectin assays, potato can serve as a specific marker for rat thyroid tumors. The cathepsin B contained in potato effectively inhibits the invasion of murine melanoma cells, and purified extracts from potato tubers show antioxidant and free-radical-scavenging effects in vitro. Thus some people use potato juice as an anticancer remedy, and this has a certain scientific basis, though its effects should not be exaggerated.
Moreover, when solanine and chaconine found in potato are mixed 1:1 at 5 mmol/L and added to small-intestinal cells of interleukin-10-deficient mice, they can damage intestinal epithelial cells, worsen colonic tissue injury, and induce inflammatory bowel disease in these gene-deficient mice, though they have no effect on normal mice. Therefore, not everyone is suited to drinking raw potato juice; patients with preexisting colitis should not use it.
Besides a certain anticancer effect, raw potato juice also relieves the pain caused by gastric and duodenal ulcers. Wash fresh (unsprouted) potatoes (unpeeled), chop finely, pound, and squeeze juice. Take 1-2 tablespoonfuls each morning on an empty stomach, adding an appropriate amount of honey, and continue for 2-3 weeks; this treats the pain caused by gastric and duodenal ulcers.
Grind potato with vinegar into a juice and apply to the affected area, reapplying as it dries without interruption; this treats mumps. Slice raw potato, pound it into a paste, and apply externally to the affected area; this treats skin eczema. When treating eczema this way, change the paste as it dries, and it may be changed many times over a day and night. Generally after 1-2 external applications the affected area improves markedly, and after 2-3 days the eczema largely resolves.