There is an urgent need for methods allowing for a fast, non-invasive, sensitive and selective monitoring of the effectiveness of anticancer drugs during the course of a chemotherapeutic treatment of cancer patients. The possibility of predicting and controlling the efficiency of chemotherapeutic agents for every patient individually enables a personalized therapy with largely improved success rates. The results presented herein demonstrate that Raman microspectroscopy is perfectly suited to monitor the impact of chemotherapeutic agents on living cells. The influence of the clinically well-established chemotherapeutic docetaxel on both the morphology and also biochemistry of living colon cancer cells (HT-29) has been studied by means of Raman spectroscopy in combination with modern chemometric approaches. The work presented paves the way for establishing Raman spectroscopy as a monitoring tool of the effectiveness of a chemotherapy treatment and can therefore be seen as a step towards personalized therapy.