Culpeper placed comfrey under Saturn, the cold, binding, earthy planet, a fitting ruler for a dark-rooted plant of heavy clay reputed to bind and mend. In folk correspondence it carries meanings of healing, safety in travel and the mending of what is broken, whether bone or bond. A plain caution belongs with its history: comfrey contains pyrrolizidine alkaloids and is now known to be harmful, particularly to the liver, if taken internally, so its old use as a medicinal tea is given here only as folklore and not as anything to be repeated. Its symbolism of knitting-together and safe return remains, drawn from the genuine gluey, healing character the old herbalists prized.
Regulators in the United Kingdom, Germany, Canada and the United States have all restricted comfrey products since the 1990s and 2000s, removing internal preparations from sale or requiring warning labels once the pyrrolizidine alkaloid risk to the liver was firmly established by toxicological research, a case where old folk medicine was investigated by modern science and found genuinely to carry a real, if usually low-level, risk rather than being simply dismissed or simply confirmed. Comfrey remains legal and popular as a garden compost activator and mulch, valued today for the same fast, nutrient-rich growth that once recommended it as a wound herb.