Alkalies should ordinarily be given before meals, especially if given to promote the secretion of hydrochloric acid (although this action is not reliable). Half an hour or so should be allowed for their passage into the intestines. If used to reduce gastric acidity, they should be given one hour or more after, meals, and often in repeated doses. For this purpose, alkaline hydrates and oxids should usually be preferred to carbonates. A common error consits in regarding neutral salts of alkaline metals, as alkalies.

Acids should be given after meals. Hydrochloric or other acids used to supplement deficient hydrochloric acidity should seldom be given less than an hour after meals, in order to let the stomach do what it can in this direction, and they are often needed in several doses at intervals of half to one hour. They should not be given after the stomach has emptied itself. The attempt to reduce hyperchlorhydria by administering an acid before meals usually fails.

Hitters and other remedies used as spurs to appetite and gastric secretion should be given shortly before meals.

Drugs which have a local irritant action, unless for some reason, this is desired, should be given during or after a meal, in order to secure dilution and admixture with the stomach contents.

Drugs intended to act locally on the stomach, as bismuth, emulsions of bismuth etc., with purpetrol, hydrogen peroxide and other detergents, should be given three or four hours after a meal and the interval between meals should be lengthened as much as possible to allow time for their action.

Nauseating drugs should be given immediately after a meal, if their local effect can be prevented by admixture of stomach contents; otherwise, they should be given as the last group.

Remedies intended to act mainly on or in the intestine, should be given about three hours after a meal and in capsule, if they are decomposed by the gastric juice. Most gelatin capsules do not dissolve within an hour but salol or keratin coatings may be employed for pancreatin etc. Many substances, such as salol, sal-acetol, iodipin etc., are not decomposed to any degree in the stomach and hence may be given immediately after a meal.

Saline cathartics act more energetically if taken half an hour or so before breakfast or other meals and may fail if given at night when the patient is soon to be quiet in bed: Other cathartics, intended to act from a single administration, are best given at bedtime. Laxatives used regularly, in small dose, as cascara, are best given with meals, whether before or after, being a matter of indifference, unless they cloy the appetite if given before or disturb the stomach if given after.

When there is no particular indication as to time with reference to meals, it is usually more convenient for the patient to take medicines at meal times rather than several hours afterward. The strength of patients may often be conserved by following this rule and greater regularity is insured in ambulant patients.

Corrosive medicines of all kinds, such as acids, mineral salts of iron etc., should be given sufficiently diluted, and should be drunk through a tube or the tongue should be used as a trough, and the mouth should be immediately rinsed, in either case, preferably with a dilute alkaline solution, as of soda and borax.

Chocolate may be used to disguise the taste of quinine and other bitter drugs. Cod liver and castor oils may be given in whisky, or milk, or after salt has been placed on the tongue. Jam, apple sauce etc., may be used to disguise the taste of some medicines, or they may be placed between pieces of bread. Iodides, salicylates etc., may often be given in milk. Iron salts should usually be given in syrups - never in mucilages - both to disguise the taste and to prevent corrosion.

The food and digestive juices contain various substances more or less incompatible with certain medicines; for example, starch with iodine, hydrochloric acid with calomel, hydrochloric acid, proteins and mucin with silver salts, tannin with alkaloids, iron and various other substances; gummy substances with iron. To what degree these incompatibilities are of consequence or how far they can be avoided, must be considered in each instance.