It is hoped the scheme will help cut the number of missed appointments
A free text message "reminder" service is being piloted at a Cornish hospital.
It is hoped the project, at the Royal Cornwall Hospital in Truro, will help cut the number of outpatients who miss appointments.
The texts, sent to patients' mobile phones, list the date, time and location of appointments and include a number to call if there is a problem.
The Royal Cornwall Hospitals NHS Trust says thousands of pounds are wasted on missed clinics.
In 2008 a total of 37,289 outpatient appointments were missed at the hospital without prior notice - the equivalent of just under nine per cent of all appointments scheduled.
The month-long pilot, which has been running for two weeks, is already being hailed a success.
The messages are only being sent to people who have given their consent but so far 10% of patients contacted have called to change appointments or to say they no longer need to attend, the hospital said.
Karen Murray, project lead, said: "Even if we just prevent 20 missed appointments we have had a success and it will pay for the setting up of the service.
"Once the trial is over the service will be reviewed and could be rolled out across other departments.
"We view this as a long term exercise - it could be used for other things such as letting people know that their results are available."