Natures aid comfrey oil 150mlnatures aid comfrey oil is manufactured by extracting the goodness from the finest quality comfrey root and comfrey herb this is achieved by slowly infusing the comfrey in a soothing natural oil comfrey is often called knitbone and has been highly valued since roman times recommended intake gently massage into the skin pack size 150ml for external use only and not recommended for use during pregnancy or when breastfeeding suitable for vegetarians and vegans