A method for automatically monitoring the penetration behavior of a trocar held by a robotic arm and monitoring system is provided. The method and system automatically monitors the penetration behavior of a trocar held by a robotic arm and/or an instrument guided through the trocar into a body cavity through an incision in the surface of the body of a patient during a surgical procedure. At least one measured value is recorded, by which a change in a force effect on the surface of the body of the patient may be determined, and automatic evaluation of the measured value with regard to a reference measured value is conducted. Comparison of the change in the measured value or the change in the force effect with a threshold value is made, and an indication in the event of the threshold value being exceeded is outputted.