A spoonful of sugar may make the proverbial medicine go down, but Mary Poppins notwithstanding, there are lots of medicines around these days that do better alone--bad taste and all.

In fact, in some cases a spoonful (or a few spoonsful) of sugar or anything else may inhibit your medicine's work, or make it work too well . . . On the other hand, of course, there are the medicines that should never, never go down without something in the stomach.

How's a person to know?

Look on the pill bottle and chances are it says, "Use as directed."

Do you remember what your doctor "directed"?

There has been substantial emphasis on drug interactions--what drugs don't go with what other drugs--but too little, perhaps on how to take your medicine. Pharmacists are keenly aware of this problem and many are moving to provide on-the-spot Baedecker-like drug guides.

In addition to the technical granddaddy of drug books, the Physician's Desk Reference, there has been a publishing deluge of books about drugs, most of which are of limited usefulness. With a few notable exceptions:

Good Housekeeping Guide to Medications by Dr. Judith K. Jones (Hearst Books, $14.95). Jones is head of the Food and Drug Administration's "Drug Experience" section. Her book includes many over-the-counter drugs as well as the prescription variety. "It has only been about four years since the studies began to show that food could interfere with the absorption of drugs," says. Jones, "and there are some curious things. For example food does interfere with Ampicillin, an antibiotic, but not with Amoxicillin, another antibiotic." Although Jones' book contains a great deal of general information, there has not been a new edition since 1980, so it is missing many of the newer prescription drugs.

The Physicians' and Pharmacists' Guide to Your Medicines (Ballantine, $9.95). Probably the best technical book for the layman (despite its title), this one is put together by the United States Pharmacopeial Convention, the nonprofit, nongovernmental organization charged with setting standards on strength, quality, purity, packaging and labeling of drugs. USP--whose standards are enforced by the FDA--has been publishing its pharmacopeia for medical professionals since 1820.

Family Guide to Prescription Drugs by Dr. Dorothy L. Smith, PharmD. (Pharmex, $3.29). This is the most easily read and quickly absorbed. Smith, who is director of clinical affairs of the American Pharmaceutical Association, initially prepared one-page flyers on prescription drugs to be distributed by pharmacists. These evolved into plasticized cards kept by drug stores in loose-leaf binders accessible to customers. The cards evolved into the book which deals, as Smith puts it, "with the top 200" (prescription drugs).

For example:

Propranolol: A medicine for high blood pressure and other heart ailments. About it she writes:

"Take this medicine with food unless otherwise directed.

"Try to take the medicine at the same time(s) every day."

On the same page she warns against taking "any of the following without the approval of your doctor or pharmacist: cough, cold or sinus products, asthma or allergy products or diet or weight reducing-medicines."

Dicyclomine (Bentyl): "Take the medicine 30 minutes before a meal unless otherwise directed . . ."

Theophylline (an asthma medicine): "It is best to take this medicine on an empty stomach with a glass of water. However, if it upsets your stomach it may be taken with some food followed by a glass of water . . ."

Aspirin-Codeine: "It is best to take this medicine with a glass of milk or food to help prevent stomach upset . . ." (The same is true of plain aspirin.)

Acetaminophen-Codeine: "The medicine may be taken with food or a glass of water . . ."

Among other drugs mentioned that should NOT be taken with food: Tetracycline (an antibiotic). "Should not be taken less than one hour before or two hours after drinking milk or milk products." (Calcium and milk prevent the tetracycline from being absorbed. This was one of the earliest examples discovered of food interfering with the way medicine works.)

Smith's more extensive Medication Guide is available from Philadelphia publisher Lea & Febiger, 600 Washington Square, Philadelphia, Pa. 19106 ($29.50).

If the Family Guide is unavailable at your bookstore, write the publisher: PHARMEX, Automatic Business Products, Co. Inc. Tuckle Road, P.O. Box 57, Willimantic, Conn. 06226.

For information on subscribing to the United States Pharmacopeial Convention's newsletter, "About Your Medicines," write USP DI, Publications Dept.; 12601 Twinbrook Pkwy., Rockville, Md. 20852.