American Express -- The office is on Theodor-Heuss-Allee 112 (tel. 069/97970), some 4km (2.5 miles) from the city center (S-Bahn: Westbahnhof). Offices are open Monday to Friday 9:30am to 6pm and Saturday 10am to 1pm.
Bookstores -- The best English-language bookstore is British Bookshop, Börsenstrasse 17 (tel. 069/280492; U-Bahn/S-Bahn: Hauptwache). It's open Monday to Friday 9:30am to 7pm and Saturday 9:30am to 6pm.
Currency Exchange -- There are multiple facilities for the exchange of international currencies at the Frankfurt airport.
Dentists & Doctors -- For an English-speaking dentist or doctor, call tel. 069/19292 to arrange an appointment.
Drugstores -- For information about pharmacies open near you, call tel. 069/19292. Otherwise you can go to Kissel-Apotheke, Mörfelder Landstrasse 235 (tel. 069/68974730).
Emergencies -- Dial tel. 110 for the police; tel. 112 for a fire, first aid, and ambulance; and tel. 069/6607271 for emergency dental service.
Internet Access -- Head for CyberRyder, Tongegasse 31 (tel. 069/91396754; www.cyberyder.de), open Monday to Friday 9:30am to 10pm, Saturday 10am to 10pm, and Sunday noon to 10pm. Internet connections cost 1.60€ ($2.10) for 15 minutes. There are several other Internet cafes in Frankfurt as well; the best place to search for Internet cafes is along Elizabethstrasse, across from the Hauptbahnhof in central Frankfurt.
Luggage Storage & Lockers -- Lockers can be rented and luggage stored at the Hauptbahnhof.
Post Office -- There's a post office at the Hauptbahnhof (tel. 069/97511004), open Monday to Friday 6:30am to 9pm, Saturday 8am to 6pm, and Sunday and holidays 11am to 6pm.
Restrooms -- There are many decent public facilities in central Frankfurt, especially in the Altstadt.
Safety -- Frankfurt is a relatively safe city, but you should still stay alert at all times. Stay out of the area around the Hauptbahnhof at night, as muggings are frequent.