A communication terminal includes an obtaining unit, a judging unit, a removing unit, and a transmitting unit. The obtaining unit obtains a phone number which is associated with a message from a transmitter. The judging unit determines whether an international code precedes a telephone number used by the transmitter, and further for generating a first control signal when the phone number includes an international code preceding the telephone number. The removing unit removes the international code from the phone number in response to the first control signal to get the telephone number only. The transmitting unit communicates with the transmitter using the telephone number only.