Pyogenic flexor tenosynovitis (PFT) is still the most serious infections of the hand. If the typical cardinal signs of PFT according to Kanavel exist, the indication for surgery should be made immediately. The consequential damage of a delayed surgery with enormous restrictions on the movement of the fingers due to the destruction of the sliding layers and massive adhesions are so serious that conservative therapy attempts are very difficult to justify. The results of Hand therapy after delayed surgery are often disappointing. The rapid surgical intervention and the early opening and relief as well as the irrigation of the tendon sheath can end the disease, the destruction of the sliding layers and the severe pain almost immediately. Quick recognition and quick action are important. With early intervention, normal hand function can often be completely restored.