Again not exactly culinary, but here is some cosmetic advice from the 11th century Macer Floridus:
93 Its (wormwood) ash blackens the hair if mixed into a wax ointment and frequently applied
490 It is also said that if you often enjoy betony in wine, a leaden (plumbeus) skin tone departs and the previous better tone returns.
570 It (chamomile) also removes scaly skin and moles on the face it you lay it on pounded, on its own or with honey.
836 The bulb (of the lily), boiled and well mixed with a wax ointment, smooths wrinkles on the face, removes all blemishes from the skin, drives out scabies, and cleans the face of scaly skin.
881 The juice of sage, it is said, blackens the hair if you often anoint it under the warm sun.
1020 Mixed with honey, it (rocket) is said to clear the skin of blemishes and the face of moles.
1125 Its (onion) juice, mixed with honey, makes dim eyes see brightly, and mixed with vinegar, it removes blemishes of the skin, but you must rub it on often.
1375 Oil is produced from violets the same way as from rose flowers. It is useful in many illnesses … you can also drive out dandruff of the head with this oil.
1518 A drink of hyssop, fresh or dried, taken often is said to give the face an exceedingly beautiful colour. (…) Boiled and laid on the skin, it softens all blemishes of the skin (livores).
1594 It (Cyprus sedge) aids the viciousness of the armpits (alarum vitiis) if mixed with oil.
2045 Anaxilaos teaches us this: If a maiden at the time that her breasts begin to swell frequently anoints them with the juice of hemlock, they will always remain of moderate size and upright. And if you lay the green herb, pounded, on the breasts, it suppresses lactation.
2077 Mixed with natron and applied as a plaster, it (pepper) softens all skin blemishes.
2129 An odor of the mouth that passes the normal measure is alleviated by eating it (galingale).
2139 It (ceodary) drives from the mouth the odour produced by garlic, and no less that by drinking wine in excess.
2158 Pounded well and mixed with strong vinegar, it (cinnamon) removes ugly moles if you lay it on the face.
2176 (Both kinds of costus root) clear the face of moles if they are applied pounded with honey.These are fairly standard recipes, and in proportion to the entirety of the work, they do not take up an inordinate amount of space. It is notable, though, how much attention a monastic writer around 1060 pays to preparations that beautify the face.
Again, Cyprus sedge, ceodary, and galingale remind us that the olfactory world of the Middle Ages was not so overwhelmingly awful that body odour or bad breath (“that passes the normal measure”) were not noticed and addressed. As to the application of hemlock to preserve the beauty of youthful breasts, the author refers to a specific ancient authority which suggests no personal experience. I sincerely hope this was not something anyone tried out. Hemlock is one of relatively few European plants that will absolutely kill you if you eat it. It should not need saying that liberally applying it to the skin is neither wise nor safe.
The Macer Floridus is a herbal that was extremely popular throughout the Middle Ages and the Renaissance in all of Europe, and especially in Germany. It was most likely written in the mid-eleventh century by Odo of Meung, but this is somewhat uncertain and the early version could date from as early as the ninth century. Its final form of 77 chapters, drawing on material from Constantinus Africanus, certainly existed by 1100. We know with certainty that it was not authored by the classical Roman writer Aemilius Macer to whom early editors ascribed it.
The Macer is a relatively brief treatment of the pharmaceutical properties of various plants, drawing on various classical and medieval sources. It does not contain culinary recipes, but some remarks in it are nonetheless interesting from that perspective. I excerpted several paragraphs I found interesting with a view to culinary preparation, feasting, and lifestyle medicine. It should not need saying that these are not medical recommendations. While some recipes in Macer may actually have an appreciable effect, others can be seriously dangerous, and none hold up to modern evidence-based practice.