Under biological conditions plants have to cope with reactive oxygen species (ROS), which often react radically and are therefore responsible for oxidative damage in cells. Normally, the production of ROS is compensated by a defense network consisting of various antioxidants but under unfavorable environmental conditions like drought their production can increase dramatically. As the availability of water is of great importance for plant growth, one focus of this applied work is on the changes of antioxidants in seasoning herbs induced by drought. As there is also an increasing interest of food industry in aromatic herbs because of their antioxidative properties another focus of this work is on the changes of antioxidants during drying, storage and processing. In general, herbs can improve flavour, avoid deterioration and enrich foods with vitamins, but the latter are sensitive to e.g. water loss or heat and can degrade easily. Therefore, in these studies field grown plant material is dried, stored and processed in different ways before examining contents of antioxidants to simulate industrial conditions and study the degradation processes.