Chinese Cinquefoil Herb Classic Formulas

Primary Actions

Clears heat and resolves toxicity - Wei Ling Cai is used for sores, boils, carbuncles, and toxic swellings when redness, inflammation, and damp-heat are prominent.
Cools blood and checks dysenteric diarrhea - it is especially valued for chronic dysentery with blood, lingering intestinal heat, and hemorrhoidal bleeding.
Relieves abdominal pain from heat-type dysentery - the herb is suited to cramping abdominal pain with bloody or persistent diarrhea rather than to cold-deficiency loose stool.
Can be used externally for toxic swelling and bleeding lesions - powders, fresh preparations, or washes extend its use beyond the internal intestinal sphere.

Wei Ling Cai with Bai Tou Weng, Huang Bai, and Ma Chi Xian (委陵菜配白头翁黄柏马齿苋) - major combination logic for dysenteric diarrhea with heat, blood, and toxicity.
Single-herb Wei Ling Cai decoction or powder - traditional practice allows it to be used alone for chronic dysentery, hemorrhoidal bleeding, or toxic swelling when the pattern is clear.
Large-dose heat-bleeding use (委陵菜重用) - some later practitioners extend the dose upward when hemorrhoidal or uterine bleeding clearly reflects heat and toxic stasis.

TCM Wiki lists Wei Ling Cai / Chinese Cinquefoil Herb as bitter and cold, entering the Liver and Large Intestine channels, with actions of clearing heat, removing toxicity, cooling blood, and checking diarrhea.
The Chinese Pharmacopoeia entry reproduced by ShennongAlpha identifies the herb as Potentillae Chinensis Herba, the dried aerial part of Potentilla chinensis, indicated for dysentery with abdominal pain, persistent diarrhea, bleeding hemorrhoids, and carbuncle or swelling with toxicity.
American Dragon adds that Wei Ling Cai can be used by itself, is paired with Bai Tou Weng-class dysentery herbs, and is contraindicated in Yang deficiency with cold or Spleen-Stomach deficiency cold.