As for staying healthy, don't drink the tap water in Cairo -- even at the best hotels. It's also a good idea to avoid raw vegetables, unpeeled fruit and street food. Finally, always have change on hand. Baksheesh is the word for tipping -- and it is a way of life there. Expect to tip toilet attendants 1 L.E or, possibly, be denied use of the facility.
Tourist disease. Food in Egypt can be a hazard. You can get sick and it will ruin your vacation.
Unique Suggestions: Even if you are prepared to the "Tourist disease" it sometimes will not be helpfull. Our Immodium does not work in Egypt! Just go to a local Chemist or Drugstore. They will know what to give you.
Chemists and drugstores are abundant in Egypt and not hard to find.
I call this a tourist trap because it is the best way to get you to read it. Don't drink the water. I don't care where you stay: it's not even safe in the most expensive, fanciest, top-of-the-line hotels. (I speak from sad experience.) Avoid anything washed in water--like fresh fruit or vegetables for your salad. And if you decide to ignore my advice, don't bother with over-the-counter medication. It's like taking sugar pills. Get a prescription in advance for something like Cipro (U.S. name). Only a prescription drug will be powerful enough to get you back out of the bathroom.