It's safe to drink tap water and eat to your heart's content everywhere in Japan (pregnant women, however, are advised to avoid eating raw fish and to avoid taking hot baths). Although Japan had nine cases of mad cow disease after its first confirmed case in 2001, all slaughtered cows must now be checked for the disease before the meat is authorized for consumption. To prevent the spread of avian and H1N1 flu, all incoming passengers are monitored upon arrival at Narita Airport for fever; those with a higher than normal temperature may be quarantined. To be on the safe side, therefore, you may opt for an influenza vaccine before departing from home.
Otherwise, you don't need any inoculations to enter Japan. Prescriptions can be filled at Japanese pharmacies only if they're issued by a Japanese doctor. To avoid hassle, bring more prescription medications than you think you'll need, clearly labeled in their original containers, and be sure to pack them in your carry-on luggage. But to be safe, bring copies of your prescriptions with you, including generic names of medicines in case a local pharmacist is unfamiliar with the brand name. Over-the-counter items are easy to obtain, though name brands are likely to be different from those back home, some ingredients allowed elsewhere may be forbidden in Japan, and prices are likely to be higher.
What to Do If You Get Sick Away from Home
Tokyo has some Western-trained physicians and many more who speak some English. If you get sick, you may want to contact the concierge at your hotel -- some upper-range hotels have in-house doctors or clinics. Otherwise, your embassy in Tokyo can provide a list of area doctors who speak English, as can the local tourist office. You can also contact the International Association for Medical Assistance to Travellers (tel. 716/754-4883, or 416/652-0137 in Canada; www.iamat.org), an organization that lists many local English-speaking doctors and also posts the latest developments in global outbreaks. Otherwise, if you can't find a doctor who can help you right away, try the local hospital. Many have walk-in clinics for cases that are not life-threatening. Doctors and hospitals generally do not accept credit cards and require immediate cash payment for health services.
Healthy Travels to You -- The following government websites offer up-to-date health-related travel advice.
Tokyo is one of the safest cities in the world. In all the years I've lived and worked in Tokyo, I've never had even one fearful encounter, and I never hesitate to walk anywhere any time of the night or day. If you lose something, say on a subway or in a park, chances are good that you'll get it back.
That being said, however, crime -- especially pickpocketing -- is on the increase, and there are precautions you should always take when traveling: Stay alert and be aware of your immediate surroundings. Be especially careful with cameras, purses, and wallets, particularly in crowded subways, department stores, or tourist attractions (such as the retail district around Tsukiji Market). Some Japanese caution women against walking through parks alone at night.