From the book linked above (starting at around page 54):
"In the hygiene of travel by land Gilbert commends a preliminary catharsis, frequent bathing, the avoidance of repletion of all kinds, an abundance of sleep and careful protection from the extremes of both heat and cold. The strange waters may be corrected by a dash of vinegar. Some travelers, he tells us, carry with them a package of their native soil, a few grains of which are added to the foreign waters, as a matter of precaution, before drinking. The breakfast of the traveler should be light, and a short period of rest after a day's travel should precede the hearty evening meal. Leavened bread two or three days old should be preferred. Of meats, the[pg 54]flesh of goats or swine, particularly the feet and neighboring parts, which, Gilbert tells us, the French call gambones, the flesh of domestic fowls and of the game fowls whose habitat is in dry places, is to be preferred to that of ducks and geese. Of fish, only those provided with scales should be eaten, and all forms of milk should be avoided, except whey, "which purifies the body of superfluities." Fruits are to be eschewed, except acid pomegranates, whose juice cools the stomach and relieves thirst. Boiled meats, seasoned with herbs like sage, parsley, mint, saffron, etc., are better than roasted meats, and onion and garlic are to be avoided.
"The primitive conditions of land travel in the days of Gilbert are emphasized by his minute directions for the care of the feet, which he directs to be rubbed briskly with salt and vinegar and then anointed with an ointment of nettle-juice (urtica) and mutton-fat, or with a mixture of garlic, soap and oil. If badly swollen, they should be bathed, before inunction, with a decoction of elder-bark and other emollients.
"In travel by sea, Gilbert tells us the four chief indications are to prevent nausea, to allay vomiting, to palliate the foul odor of the ship and to quiet thirst.
"For the prevention of nausea he recommends the juice of acid pomegranates, lemons, etc., or a decoction of parsley or sweet cicely (cerfolium). The traveler should endeavor to sit with his head erect, should avoid looking around, but maintain his head as immovable as possible, and support himself by a firm grasp upon some beam of the ship. Some sweets may be sucked, or he may chew a few aromatic seeds. If vomiting ensues, acid or sweet pomegranates, figs or barley-sugar (penides) may be taken sparingly, but no food should be ingested until the stomach is thoroughly quieted. Then the patient may take a little stomatichon or dyantos, and a small portion of digestible food. As the diet must necessarily consist largely of salty food and vegetables, these should be cooked in three or four different waters, and then soaked in fresh water. A little aromatic wine will also benefit the patient, and a few aromatic seeds chewed in the morning are also of service.
"The effect of the foul odors of the ship may be combatted by the use of aromatic electuaries, "which comfort the heart, the brain and the stomach." The patient should be removed to some quiet portion of the ship, as distant as possible from the channels for the discharge of the bilge-water, and short walks upon the upper[pg 55]deck will contribute to convalescence. Frequent changes of clothing will palliate the annoyance of fleas and pediculi. Drinking water may be purified by aëration, or by straining, boiling and subsequent sedimentation and removal of the sediment by filtration through fresh and clean sand. For the wealthy, the water may be distilled in an alembic, if such an apparatus is obtainable. Avicenna says that bad water may be corrected by the addition of vinegar. Exposure to the midday sun and to the nocturnal cold, constipation and diarrhoea should be avoided, and prompt attention should be given to all disorders of the health.
"Dominus autem omnia dirigat in tranquilitate. Amen."
This seems to be an online text in the original Latin, of Gilbertus' Medicinal Compendium. You just click on the small Left-pointing arrow at the bottom of this page; it takes you to the alphabetized list of medicines used by the Physician.
If you're either luckier or smarter than me, you might be able to locate an online copy of the Compendium, translated in to English.