The US Food and Drug Administration (FDA) has officially cleared edible computers to be used in medical applications for monitoring patient health.

After four years of discussions, Proteus Digital has received approval for its Ingestion Event Marker, a silicon sensor about 1mm square that is encased in a pill and is meant to be swallowed. Once stomach acid reaches the sensor it acts as an electrolyte, generating 1-2 volts of power between the copper salt cathode and a magnesium anode.

While it carries no aerial itself, the chip emits a tone that can be picked up on a patch worn on the outside of the body. The patch then relays the sensor's data (along with heart rate and body movement of the patent) to a mobile phone with the right software application installed.

The sensor doesn't last long for sustained operation and is passed through the gut "like high-fiber food," according to the manufacturer. "We are very much looking forward to bringing the benefits of our ingestible sensor to the American public in the form of innovative product offerings," said Dr. George M. Savage, co-founder and chief medical officer at Proteus Digital in a statement.

Before you start getting images of a Fantastic Voyage scenario, the current technology that has been approved is very basic. The sensor is designed to ensure that medication is taken correctly and on time by providing a log of ingestion, and we're still years away from the medical robots that can maneuver through the body and perform repairs, as envisioned by some so-called technology gurus.

Nevertheless, the FDA approval is an important step in allowing the use of wetware, or implantable computers, to improve human health. The EU has already approved the Proteus Digital designs and certified them as safe for human use. With the FDA decision, the company now has access to the most expensive healthcare market in the world.

"The FDA validation represents a major milestone in digital medicine. Directly digitizing pills, for the first time, in conjunction with our wireless infrastructure, may prove to be the new standard for influencing medication adherence and significantly aid chronic disease management," said Dr. Eric Topol, professor of genomics at The Scripps Research Institute. ®