C
Erysipelas (f; GMH; MAD); Escherichia (f; HH2); Fever (f; CRC; DAA; MAD; PIP); Flu (f;
CRC; DAA; LMP; MAD; PHR); Fistula (f; HAD); Gastrosis (f; CRC; FEL); Headache (f;
CRC; FEL); Hematemesis (f; HAD); Hemoptysis (f; CRC; DAA; LMP); Hoarseness (2; APA;
KOM; MAD; PIP); Immunodepression (1; CAN); Induration (f; CRC; JLH); Infection (1;
CRC); Inflammation (2; CAN; FAD; KOM; PH2); Laryngosis (1; CAN; FEL); Low Blood
Pressure (1; APA); Mucososis (2; CRC; FAD; KOM; PH2); Neurosis (f; CRC); Nicotinism (f;
PH2); Ophthalmia (f; CRC); Pertussis (f; CAN; FEL); Pharyngosis (2; KOM; PH2; PIP);
Phthisis (f; CRC; DAA); Plethora (f; CRC); Pleurosis (f; MAD); Pulmonosis (f; CRC; FAD);
Respirosis (2; KOM; 2; PIP); Rheumatism (f; CRC; PH2); Rhinosis (f; CRC; FEL); Scrofula
(f; CRC; FEL; GMH); Sinusosis (f; CRC); Sore Throat (f; PHR; PIP); Stomatosis (2; APA;
PHR; PH2; PIP); Swelling (1; CAN; CRC; HH2; MAD); Tonsillosis (f; PHR; PIP); Tracheosis
(f; MAD); Tuberculosis (f; CRC; DAA; DEM; MAD); Tumor (f; CRC); Wart (f; MAD); Water
Retention (f; CRC; PIP).
Dosages (Coltsfoot) — 2 tsp powdered leaf/cup water (APA; WIC); 0.3–0.6 g solid leaf extract
(PNC); 2–4 ml liquid leaf extract (PNC); 4.5–6 g leaf, 0.6–2.0 ml liquid extract (1:1 in 25%
ethanol) 3 ×/day (CAN); 0.6–2.0 g herb as tea 3 ×/day (CAN); 2–8 ml tincture (1:5 in 45%
alcohol) 3 ×/day (CAN); 2–8 ml syrup (1:4 liquid extract in syrup) 3 ×/day (CAN); 4 g root
as diaphoretic (MAD); 1.5–2.5 g leaf or flower/cup tea, to 6 g day (PH2); 0.6–2 ml liquid
flower extract (PNC).
Contraindications, Interactions, and Side Effects (Coltsfoot) — Class 2b, 2d (flower); long-
term use discouraged. 2b, 2c, 2d (leaf); do not exceed recommended dose; not for long-term
use (AHP). Commission E reports flower, herb, root not permitted for therapeutic use. Contains
hepatotoxic pyrrolizidine alkaloids (PAs) in all plant parts. Leaf is permitted for oral use.
Contraindications in pregnancy and lactation. CAN cautions that the PAs are genotoxic,
carcinogenic, and hepatotoxic. Because of the PAs, coltsfoot use in pregnancy and lactation
is to be avoided (CAN). Dosage maximum 10 g PA/day (herbal tea) or maximum 1 g PA/day
(extracts, expressed sap) for maximum 4–6 weeks/year (AEH). Commission E advises not to
take more than 4 to 6 weeks of the year at 4.5 to 6 g/day. This is the only herb (1.5–6 g
leaf/day) except related Petasites with toxic PAs still tolerated by Commission E. Still, CAN
cautions that coltsfoot is phototoxic in guinea pig skin. In guinea pig sensitization experiments,
it showed weak allergenic capacity, possibly due to the sesquiterpene lactones present in the
plant. PAs are toxic to humans, with liver damage with cirrhosis and ascites, or seneciosis, or
veno-occlusive disease (VOD) reported in almost all cases of severe or fatal intoxications,
from intakes of 0.5 mg/kg to 3.3 mg/kg (AEH1). Effective July 1996, the AHP Board of
Trustees recommends that all products with botanical ingredient(s) that contain toxic PAs,
including Borago officinalis, display the following cautionary statement on the label, “For
external use only. Do not apply to broken or abraded skin. Do not use when nursing” (AHP).
Canadians do not allow in food (Blackburn, 1993). Bisset says there is no danger of acute
poisoning when used as prescribed (Bisset, 1994). Hepatotoxicity of coltsfoot may be due to
senkirkine (~150 ppm), highlighting the dangers of chronic exposure to even low doses of
PAs. Rats fed more than 4% coltsfoot in their diet develop hepatic tumors. Newborn rats are
more susceptible than weanlings to hepatotoxicity of senkirkine despite lacking the hepatic
microsomal enzymes required to produce the toxic pyrrholic metabolites. Fatal hepatic veno-
occlusive disease was documented in a newborn infant whose mother chronically consumed
herb teas during pregnancy (coltsfoot and senecio specified). The mother exhibited no signs
of hepatic damage again suggesting increased sensitivity of the fetal liver to PA toxicity.
Animal studies document placental transfer and secretion into breast milk of unsaturated PAs
(CAN). Excessive doses may interfere with blood pressure and heart therapy (CAN).