DO take iron medications after your meal. Iron, taken orally, causes gastrointestinal disturbances such as gastric distress, nausea or diarrhoea.

DON'T take iron medications with antacids such as calcium carbonate, aluminium hydroxide and magnesium hydroxide, as they reduce iron absorption, possibly by neutralising the gastric activity.

DO take iron medications with vitamin C, as vitamin C accelerates the absorption of iron.

DO chew your antacids thoroughly for maximum efficiency.

DO wait an hour after your meal before popping an antacid - it will be effective longer (for three to four hours) rather than the 15 to 30 minutes when taken in a fasting state.

DON'T POP multivitamins indiscriminately, or as dietary supplements, "to keep up energy and strength". They do no more than placebos if unwarranted.

DON'T take insulin orally, as gastrointestinal enzymes destroy it. It must be administered parenterally.

DO inject plain insulin about half an hour before each meal.

DON'T take calcium, magnesium, aluminium and iron salts in combination with tetracycline as these form complexes in the gastrointestinal tract, impairing the absorption of the antibiotic.

DO take antibiotics with vitamin B complex, as these tend to destroy the normal bacterial flora that line the intestines, creating a vitamin B complex deficiency.