Medical Care

EU citizens are entitled to free medical care, You should come to Spain with the relevant form (E111) or a European Health Insurance card (EHIC).  Residents of Austria, the Netherlands and the UK may use the E111 until 31 December 2005, when it will become invalid.  Residents of other EU countries should check if their E111 transitional form is valid.  The E111 form and the EHIC do not cover dental treatment or private medical care.
Take the form of your EHIC card to your nearest health center.  Call any centro de salud (see the yellow pages for telephone numbers), provide your address and they will tell you where your nearest center is.  You will not be given a specific appointment, but a period of time within which you will be seen, so be prepared to wait.  At the reception desk you will be given a form to fill out, your doctor's name and be told to go to a certain sala. Ask who the last person in the line is: "¿Quien es el ultimo?" or listen for your name.  Note that your doctor may not speak English, so be prepared to translate your symptoms.
After the consultation, you'll be given a prescription (receta) and may need to return to the reception desk if the doctor has referred you to a specialist.  Take the  prescription to a drug store (anywhere you see a green cross sign).
Non-EU citizens must have health insurance from their country. Universities advise students to go to the Unidad Medica, Conde de Aranda, 1, Tel. 914-351-823 (Metro: Retiro). This center has English speaking doctors and is familiar with giving the recibo that must be sent to your social security / insurance company back home. This center also has dentists.

Note: There are plenty of options for you to receive quality medical care at all hours of the day and night. Madrid has public and private healthcare centers. You may think that there are big differences in the following two option, but they are really pretty similar. There is usually less of a wait and maybe a few more tests at Private facilities, but they require you to pay for your treatment up front. They will give you a bill that you can submit to your insurance company. Public facilities just ask for identification and local address. They usually don't expect foreigners to pay.

You can also get treatment at the private British / American clinic if you prefer medical services in English, which may make it easier when it comes time to submit your forms to the insurance company.

Another useful thing to know is that Pharmacies here provide a lot of medicines for common illnesses without a prescription. The Pharmacists are generally well trained and very helpful. Check around Sol to find plenty of locations, some of which stay open 24 hours a day.